All practice questions

Question 4881Question →

During a laboratory examination of lower invertebrates, a specimen is observed to have a triploblastic acoelomate body plan, a branched gastrovascular cavity with only one opening, and specialized flame cells for osmoregulation. Which phylum is characterized by these features?

Platyhelminthes

Nematoda

Coelenterata

Porifera

Show answer & explanation

Answer: Platyhelminthes

Answer

Platyhelminthes

The combination of a triploblastic acoelomate body structure, an incomplete digestive system (gastrovascular cavity), and flame cells for excretion uniquely defines members of the phylum Platyhelminthes.

Step-by-Step Solution

1

Analyze the germ layers and coelom status described in the stem.

The specimen is triploblastic (three germ layers) and acoelomate (lacks a body cavity).

This rules out diploblastic phyla (Coelenterata) and pseudocoelomate phyla (Nematoda).

2

Examine the gut completeness and excretory structures.

The specimen has an incomplete gut (gastrovascular cavity with a single opening) and possesses flame cells.

Flame cells (protonephridia) are the diagnostic excretory structures unique to phylum Platyhelminthes among lower invertebrates.

Key Concept

Structural characteristics and diagnostic organs of Phylum Platyhelminthes

Question 4882Question →

Consider two sovereign states: State X utilizes decentralized price signals and private ownership to guide resource allocation across production sectors, whereas State Y relies on central planning authorities to set output targets and fix commodity prices. When evaluating the performance trade-offs between these two economic models, which outcome highlights a primary structural drawback of State X relative to State Y?

Greater vulnerability to income inequality and the under-provision of public goods

Total suppression of consumer sovereignty and individual economic initiatives

Widespread chronic supply shortages stemming from rigid administrative price controls

Complete absence of profit incentives, leading to widespread worker apathy

Show answer & explanation

Answer: Greater vulnerability to income inequality and the under-provision of public goods

Answer

Greater vulnerability to income inequality and the under-provision of public goods

In a comparative evaluation of economic systems, decentralized market systems (represented by State X) excel at dynamic allocative efficiency but inherently suffer from market failures. Because resources flow toward profitable demand rather than social equity, market systems tend to produce unequal income distribution and under-supply public goods like national defense or street lighting. State-directed planning systems (State Y) directly control resource allocation to mitigate these specific welfare gaps, making income disparity and public goods deficits the prominent relative drawbacks of State X.

Step-by-Step Solution

1

Identify the economic system models described for State X and State Y.

State X operates a market-driven (capitalist) system relying on price signals and private ownership. State Y operates a centrally planned (socialist) system relying on administrative state directives.

Establishing the core economic framework for each state is required before conducting comparative analysis.

2

Analyze the inherent market failures associated with State X's market-driven mechanism.

Market mechanisms distribute resources based on purchasing power rather than social need, leading to income skewness and non-excludability failures in public goods provision.

Evaluating structural trade-offs requires identifying specific market failure mechanisms unique to price-directed systems.

3

Compare the potential drawbacks against the options provided to determine the valid structural limitation.

Inequality and under-provision of public goods are direct market failure outcomes of State X, whereas shortages, absence of profit motive, and loss of consumer choice characterize State Y.

Differentiating between market failures and central planning inefficiencies eliminates distractors.

Key Concept

Trade-offs and Market Failures in Comparative Economic Systems

Question 4883Question →

Match each classical theory of international trade on the left with its defining principle or primary economist on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Theory of Absolute Advantage pairs with Adam Smith's concept of producing goods using fewer resources; Theory of Comparative Advantage pairs with David Ricardo's relative efficiency and lower opportunity cost principle; Opportunity Cost Theory of Trade pairs with Gottfried Haberler's evaluation of trade using foregone output.

The Theory of Absolute Advantage is correctly matched to Adam Smith because he pioneered the idea of trade driven by absolute productivity differences. The Theory of Comparative Advantage is correctly matched to David Ricardo, who proved trade benefits arise from comparative lower opportunity costs. The Opportunity Cost Theory of Trade is correctly matched to Gottfried Haberler, who replaced the classical labor theory of value with opportunity cost analysis.

Step-by-Step Solution

1

Identify the economist and core concept associated with absolute advantage.

Adam Smith established that countries gain by specializing in products they produce more efficiently in absolute terms.

This establishes the historical foundation of free trade based on absolute cost differences.

2

Identify the economist and core concept associated with comparative advantage.

David Ricardo showed that relative efficiency (lower opportunity cost) determines mutually beneficial trade.

Comparative advantage extends trade theory to situations where one country holds an absolute advantage across all commodities.

3

Identify the modern refinement based on opportunity cost.

Gottfried Haberler reformulated comparative advantage using production possibility curves and opportunity costs rather than labor hours.

This modernizes classical trade theory by removing the restrictive assumption of the labor theory of value.

Key Concept

Foundational Theories and Economists of International Trade

Estimated Time:1m 0s

Question 4884Question →

An agricultural officer recorded the annual yield of palm oil (in metric tons) produced by a commercial farm over a 5-year period as follows: $12$ , $16$ , $18$ , $20$ , and $24$ . What is the standard deviation of the annual palm oil yield in metric tons?

Show answer & explanation

Answer: 4

Answer

The standard deviation of the palm oil yield over the 5-year period is

4\text{ metric tons}

.

The standard deviation is calculated by determining the mean yield (

18\text{ metric tons}

), taking the sum of the squared deviations from the mean (

80

), dividing by the total number of observations (

5

) to obtain a variance of

16

, and then taking the square root of

16

, which equals

4\text{ metric tons}

.

Step-by-Step Solution

1

Calculate the arithmetic mean (

\mu

) of the data set.

\mu = \frac{12 + 16 + 18 + 20 + 24}{5} = 18\text{ metric tons}

.

The mean is required to determine the deviations of individual data values.

2

Determine the squared deviations from the mean for each yield value.

(12-18)^2 = 36

,

(16-18)^2 = 4

,

(18-18)^2 = 0

,

(20-18)^2 = 4

, and

(24-18)^2 = 36

. The sum of these squared deviations is

80

.

Squaring deviations eliminates negative values so that dispersion around the mean can be aggregated accurately.

3

Compute the variance (

\sigma^2

) of the dataset.

\sigma^2 = \frac{80}{5} = 16

.

Variance represents the average of the squared deviations from the mean.

4

Compute the standard deviation (

\sigma

) by taking the square root of the variance.

\sigma = \sqrt{16} = 4\text{ metric tons}

.

Standard deviation measures dispersion in the original units of the data.

Key Concept

Standard Deviation of Ungrouped Data

Question 4885Question →

Match each oligopolistic market structure or analytical model on the left with its defining operational characteristic or price behavior on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Sweezy's Non-Collusive Oligopoly corresponds to asymmetric rival reactions and a kinked demand curve; Perfect Oligopoly corresponds to identical homogeneous goods with extreme price sensitivity; Formal Cartel Collusion corresponds to an explicit centralized agreement acting as a monopoly; Dominant Firm Price Leadership corresponds to a single leader setting market price with smaller firms acting as price takers.

Each type and model of oligopoly is defined by its unique assumptions about product differentiation, rival behavior, and coordination mechanics. Non-collusive oligopoly relies on asymmetric demand elasticity leading to sticky prices. Pure oligopoly involves identical products. Formal cartels act as explicit monopolies, while price leadership relies on a dominant firm setting prices that fringe competitors follow.

Step-by-Step Solution

1

Analyze non-collusive pricing models

Identified Sweezy's kinked demand model, which assumes rivals match price cuts but ignore price hikes, creating a broken marginal revenue curve and rigid prices.

This behavior explains why prices remain sticky in non-collusive oligopolies despite small cost fluctuations.

2

Analyze product homogeneity in oligopoly

Associated Perfect (Pure) Oligopoly with raw materials or standardized goods.

Because goods are homogeneous, consumers switch instantly if one firm changes price, enforcing severe mutual interdependence.

3

Distinguish collusive structures

Linked Formal Cartels to explicit joint-monopoly quota agreements.

Cartels represent explicit collusion designed to maximize joint profits by acting as a single entity.

4

Examine price coordination without formal contracts

Matched Dominant Firm Price Leadership with tacit coordination where smaller satellite firms adopt the leader's price.

Fringe firms face the leader's price as given, acting as price takers on the residual industry demand curve.

Key Concept

Oligopoly Typology, Mutual Interdependence, and Price Determination Models

Question 4886Question →

A sudden environmental change occurs in a habitat, favoring beetles with darker pigmentation. According to modern evolutionary theory (Neo-Darwinism), which of the following best explains the genetic basis for how this beetle population evolves over successive generations?

Individual beetles acquire darker pigmentation during their lifetime due to environmental stress and pass these somatic changes directly to their offspring.

Pre-existing gene mutations in germ cells provide dark allele variations, increasing in frequency over generations as natural selection favors darker individuals.

The environmental stress converts discontinuous phenotypic variations directly into continuous environmental modifications without altering allele frequencies.

Natural selection creates new analogous structural adaptations within the somatic cells of surviving adults to ensure immediate individual survival.

Show answer & explanation

Answer: Pre-existing gene mutations in germ cells provide dark allele variations, increasing in frequency over generations as natural selection favors darker individuals.

Answer

Pre-existing gene mutations in germ cells provide dark allele variations, increasing in frequency over generations as natural selection favors darker individuals.

Modern evolutionary theory (Neo-Darwinism) explains evolution as a change in allele frequencies within a population over time. Gene mutations in germ cells create heritable variations in the gene pool. When environmental conditions change, individuals carrying advantageous alleles experience greater reproductive success, causing those favorable alleles to become more common in the population over successive generations.

Step-by-Step Solution

1

Identify the core principle of Modern Evolutionary Theory (Neo-Darwinism).

Neo-Darwinism integrates Mendelian genetics with Darwinian natural selection, emphasizing that evolution is driven by changes in gene/allele frequencies within a population's gene pool.

Evolution occurs at the population level through genetic inheritance, not at the individual level through somatic modifications.

2

Evaluate the origin and transmission of evolutionary variation.

Random gene mutations occurring in germline cells generate new alleles, creating heritable genetic variation.

Only mutations in germ cells (gametes) are transmissible to offspring, serving as raw material for selection.

3

Determine the effect of natural selection on allele frequencies.

Individuals possessing favorable alleles (darker pigmentation) have higher differential reproductive success, increasing the dark allele frequency in subsequent generations.

Differential survival and reproduction lead to adaptation over generational time.

Key Concept

Modern Evolutionary Theory (Neo-Darwinism) and Population Genetics

Question 4887Question →

The table below shows the distribution of weekly cassava output (in bags) produced by a sample of farmers in a agricultural cooperative:

Output (Bags)	Number of Farmers ( $f$ )
$10 - 14$	$2$
$15 - 19$	$5$
$20 - 24$	$8$
$25 - 29$	$5$

What is the mean weekly output of cassava per farmer?

19.0\text{ bags}

19.5\text{ bags}

21.0\text{ bags}

23.0\text{ bags}

Show answer & explanation

Answer: $21.0\text{ bags}$

Answer

The mean weekly output of cassava per farmer is

21.0\text{ bags}

.

The correct output of

21.0\text{ bags}

is derived by determining the midpoint of each class interval (

12, 17, 22, 27

), multiplying each by its respective number of farmers, summing these products to get

420\text{ bags}

, and dividing by the total number of farmers (

20

).

Step-by-Step Solution

1

Calculate the class midpoint (

x

) for each class interval.

Midpoints are:

\frac{10+14}{2} = 12

,

\frac{15+19}{2} = 17

,

\frac{20+24}{2} = 22

, and

\frac{25+29}{2} = 27

.

For grouped data, the midpoint represents the central value of each class interval.

2

Multiply each midpoint (

x

) by its corresponding frequency (

f

) to obtain

f \times x

.

2 \times 12 = 24

,

5 \times 17 = 85

,

8 \times 22 = 176

,

5 \times 27 = 135

.

This determines the estimated total output within each interval.

3

Calculate the sum of frequencies (

\sum f

) and the sum of products (

\sum fx

).

\sum f = 2 + 5 + 8 + 5 = 20

;

\sum fx = 24 + 85 + 176 + 135 = 420

.

These totals are needed to apply the grouped mean formula.

4

Divide

\sum fx

by

\sum f

to compute the arithmetic mean (

\bar{x}

).

\bar{x} = \frac{420}{20} = 21.0\text{ bags}

.

The formula for the mean of grouped frequency distribution is

\bar{x} = \frac{\sum fx}{\sum f}

.

Key Concept

Arithmetic Mean of Grouped Data

Estimated Time:1m 30s

Question 4888Question →

Which of the following factors will cause an outward (rightward) shift in the demand curve for a normal good?

An increase in consumer disposable income

A decrease in the price of the good itself

A fall in the price of a substitute good

A reduction in total market population

Show answer & explanation

Answer: An increase in consumer disposable income

Answer

An increase in consumer disposable income causes an outward (rightward) shift in the demand curve for a normal good.

For a normal good, an increase in consumer disposable income raises overall purchasing power. Consumers purchase more of the commodity at every given price, causing the entire demand curve to shift outwards to the right.

Step-by-Step Solution

1

Distinguish between price determinants and non-price determinants of demand.

Changes in price cause movement along the demand curve, whereas changes in non-price determinants (income, tastes, substitute/complement prices, population) shift the entire curve.

To identify which option results in a curve shift rather than a movement along the curve.

2

Analyze the impact of an increase in disposable income on a normal good.

Higher disposable income increases consumer purchasing power, causing higher quantity demanded at all price levels.

Normal goods have a positive income elasticity of demand, so demand shifts rightward when income increases.

Key Concept

Determinants of Demand and Demand Curve Shifts

Estimated Time:45s

Question 4889Question →

A commercial banking system generates a total deposit expansion of $₦600,000$ from an initial cash injection of $₦150,000$ . If the central bank subsequently raises the cash reserve ratio by $5\%$ , what is the new total deposit expansion that the banking system can generate from the same initial cash injection?

₦500,000

₦350,000

₦570,000

₦45,000

Show answer & explanation

Answer: $₦500,000$

Answer

₦500,000

The option specifying

₦500,000

is correct because the initial reserve requirement of

25\%

(

0.25

), derived from

\frac{150,000}{600,000}

, increases by

5\%

to

30\%

(

0.30

). Dividing the primary cash injection of

₦150,000

by

0.30

yields a new total deposit capacity of

₦500,000

.

Step-by-Step Solution

1

Determine the initial credit multiplier and cash reserve ratio

Credit Multiplier =

4

, Cash Reserve Ratio =

25\%

The initial credit multiplier is

\frac{\text{Total Deposit Expansion}}{\text{Initial Cash Injection}} = \frac{₦600,000}{₦150,000} = 4

. Since

\text{Credit Multiplier} = \frac{1}{\text{Cash Reserve Ratio}}

, the initial Cash Reserve Ratio is

\frac{1}{4} = 0.25

or

25\%

.

2

Calculate the updated cash reserve ratio

New Cash Reserve Ratio =

30\%

(

0.30

)

The central bank increases the reserve requirement by an additional

5\%

, making the new ratio

25\% + 5\% = 30\%

.

3

Compute the new total deposit expansion

₦500,000

Using the credit expansion formula,

\text{New Total Deposits} = \frac{\text{Initial Cash Injection}}{\text{New Cash Reserve Ratio}} = \frac{₦150,000}{0.30} = ₦500,000

.

Key Concept

Credit Creation and the Credit Multiplier Formula

Estimated Time:2m 0s

Question 4890Question →

Governments frequently implement commercial policies to regulate international trade and protect domestic industries. Which of the following trade policy instruments refers to a direct financial grant or tax concession granted by the government to domestic producers to lower their production costs and boost exports?

An export subsidy

An import quota

A protective tariff

A trade embargo

Show answer & explanation

Answer: An export subsidy

Answer

An export subsidy is a financial incentive paid by the government to domestic producers to lower production costs and encourage export sales.

An export subsidy is a direct or indirect financial aid (such as cash grants, low-interest loans, or tax relief) paid by the government to domestic producers, allowing them to reduce selling prices and increase competitiveness abroad.

Step-by-Step Solution

1

Identify the key characteristics of the commercial policy instrument described in the question.

The instrument involves government financial assistance given directly to domestic producers to lower costs and encourage exports.

Commercial policy uses various monetary and quantitative instruments to influence trade flows.

2

Evaluate the choices based on economic definitions of trade barriers.

Tariffs are import taxes, quotas are physical volume limits, embargoes are total trade bans, while subsidies are direct financial payments to domestic producers.

Distinguishing between price-based tax instruments, quantitative restrictions, and direct financial subsidies ensures accurate identification of commercial policy tools.

Key Concept

Export Subsidies and Commercial Policy Instruments

Question 4891Question →

Match each market structure or market arrangement with its corresponding long-run economic efficiency and consumer welfare outcome.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Perfect Competition (Long-Run) matches with achieving allocative (

P = MC

) and productive (

P = \text{min } ATC

) efficiency; Monopoly (Long-Run) matches with failing both efficiency criteria and creating deadweight loss; Monopolistic Competition (Long-Run) matches with failing allocative efficiency and operating with excess capacity while providing product variety; Collusive Oligopoly matches with restricting industry output to set

P > MC

and maximize joint profit.

Each market structure is correctly paired according to its standard microeconomic efficiency benchmark: Perfect competition achieves full efficiency (

P = MC = \text{min } ATC

), monopoly causes deadweight loss (

P > MC

and

P > \text{min } ATC

), monopolistic competition exhibits excess capacity alongside product differentiation, and collusive oligopoly mimics monopoly output restriction.

Step-by-Step Solution

1

Evaluate Perfect Competition

In the long run, free entry/exit forces price to equal minimum ATC (

P = \text{min } ATC

, productive efficiency) and firm profit maximization sets price equal to marginal cost (

P = MC

, allocative efficiency).

Perfectly elastic demand at market price ensures optimal resource allocation and maximum consumer surplus.

2

Evaluate Monopoly

High entry barriers allow the monopolist to restrict output, charging

P > MC

and producing where

ATC

is not minimized.

This generates a deadweight loss, reducing consumer welfare below the socially optimal level.

3

Evaluate Monopolistic Competition

Tangency of the downward-sloping demand curve to ATC in long-run equilibrium results in

P > MC

and production to the left of minimum ATC (excess capacity).

While inefficient compared to perfect competition, consumer welfare benefits from product differentiation and variety.

4

Evaluate Collusive Oligopoly

Formal or informal agreements lead firms to restrict output and raise prices jointly.

Cartel behaviour replicates monopoly outcomes, transferring surplus from consumers to producers.

Key Concept

Comparison of Market Structures: Economic Efficiency and Consumer Welfare

Question 4892Question →

When a government borrows funds to construct revenue-yielding assets, such as a toll highway or a hydroelectric power plant that generates income to pay back the loan, which category of public debt does this represent?

Productive debt

Deadweight debt

Unfunded debt

External debt

Show answer & explanation

Answer: Productive debt

Answer

Productive debt is debt incurred to fund capital expenditure projects that generate revenue to cover the loan's repayment.

Productive (or reproductive) debt refers to government borrowing used for capital investments that create income-generating assets. The revenue derived from the project is utilized to service and repay the loan without creating a net financial burden on taxpayers.

Step-by-Step Solution

1

Analyze the purpose of the borrowing in the scenario.

The government is borrowing for a toll highway/hydroelectric power plant that yields revenue.

Public debt is classified primarily by its purpose, economic productivity, maturity, or place of issuance.

2

Distinguish between productive and non-productive debt categories.

Debt backed by self-liquidating, revenue-earning assets is classified as productive (reproductive) debt.

The returns from the investment cover both the interest payments and principal redemption over time.

Key Concept

Classification of Public Debt by Productivity

Question 4893Question →

When computing national income using the output method, an economist includes both the full value of raw timber sold to a furniture maker and the final market value of the furniture produced from that timber. Which difficulty in national income accounting is created by this procedure?

Double counting of national output

Underestimation of total national output

Distortion caused by price inflation

Errors in converting GDP to GNP

Show answer & explanation

Answer: Double counting of national output

Answer

Double counting of national output

The correct answer is double counting of national output. In national income accounting using the output method, only the value added at each stage or the value of final goods should be counted. Including the intermediate good (raw timber) along with the final good (furniture) results in counting the input's value twice, which artificially inflates national income.

Step-by-Step Solution

1

Identify the nature of raw timber in the production process.

Raw timber is an intermediate good used to manufacture furniture.

Intermediate goods are inputs already embodied in the value of the final good.

2

Analyze the impact of adding intermediate goods to final goods.

The value of raw timber is counted once as an input and a second time as part of the furniture's final price.

This leads directly to the problem of double counting in national income statistics.

Key Concept

Double Counting in Output Method

Question 4894Question →

In consumer utility theory, as a consumer moves downward from left to right along a standard, origin-convex indifference curve for two commodities, $X$ and $Y$ , how does the Marginal Rate of Substitution ( $MRS_{xy}$ ) behave?

It diminishes continuously as more units of

X

are substituted for

Y

.

It remains constant across all combination points on the curve.

It increases steadily as the quantity of

X

consumed rises.

It falls to zero at the point where total utility from both goods is maximized.

Show answer & explanation

Answer: It diminishes continuously as more units of $X$ are substituted for $Y$ .

Answer

The Marginal Rate of Substitution (

MRS_{xy}

) diminishes continuously as more units of

X

are substituted for

Y

.

The correct answer accounts for the principle of diminishing marginal rate of substitution. As a consumer increases consumption of Good

X

, its marginal utility (

MU_x

) decreases relative to that of Good

Y

(

MU_y

). Consequently, the consumer yields smaller amounts of

Y

for each extra unit of

X

, making

MRS_{xy}

diminish and conferring a convex shape to the indifference curve.

Step-by-Step Solution

1

Define Marginal Rate of Substitution (

MRS_{xy}

)

MRS_{xy} = -\frac{\Delta Y}{\Delta X} = \frac{MU_x}{MU_y}

MRS_{xy}

measures the rate at which a consumer is willing to give up Good

Y

to obtain one additional unit of Good

X

while keeping total utility constant.

2

Analyze the impact of moving downward along the curve

As consumption of

X

increases,

MU_x

falls (due to diminishing marginal utility), while

MU_y

rises as

Y

becomes scarcer to the consumer.

The principle of diminishing marginal utility dictates that as a good becomes more abundant, its marginal valuation declines.

3

Determine the curvature property resulting from this behavior

The slope of the curve (

MRS_{xy}

) flattens, making the curve convex to the origin.

A diminishing ratio of

\frac{MU_x}{MU_y}

directly accounts for the origin-convex shape of standard indifference curves.

Key Concept

Diminishing Marginal Rate of Substitution and Indifference Curve Convexity

Estimated Time:1m 0s

Question 4895Question →

The table below presents the national income accounting estimates for a hypothetical open economy in a given financial year:

Component	Amount ($ billions)
Personal Consumption Expenditure	450
Gross Domestic Fixed Capital Formation	180
Value of Physical Change in Stocks	30
Government Final Consumption Expenditure	150
Government Transfer Payments	35
Exports of Goods and Non-Factor Services	90
Imports of Goods and Non-Factor Services	110
Net Factor Income from Abroad	-15
Depreciation (Consumption of Fixed Capital)	40
Indirect Taxes	50
Subsidies	20

Using the expenditure approach, what is the Net National Product at factor cost ( $NNP_{fc}$ ) for this economy?

705

billion

740

billion

735

billion

925

billion

Show answer & explanation

Answer: $705$ billion

Answer

705

billion

The expenditure method sums consumption, investment, government spending, and net exports to calculate

GDP_{mp}

(

450 + 210 + 150 - 20 = 790

billion). Adding net factor income from abroad gives

GNP_{mp}

(

775

billion). Subtracting depreciation yields

NNP_{mp}

(

735

billion), and deducting net indirect taxes (

50 - 20 = 30

billion) gives

NNP_{fc} = 705

billion. Transfer payments are excluded to avoid double counting.

Step-by-Step Solution

1

Calculate Gross Domestic Product at market prices (

GDP_{mp}

) using the expenditure components:

C + I + G + (X - M)

GDP_{mp} = 450 + (180 + 30) + 150 + (90 - 110) = 790

billion

Gross domestic investment equals gross domestic fixed capital formation plus change in stocks. Transfer payments are excluded as they are non-productive transactions.

2

Adjust

GDP_{mp}

for Net Factor Income from Abroad (

NFIA

) to find Gross National Product at market prices (

GNP_{mp}

)

GNP_{mp} = 790 + (-15) = 775

billion

GNP_{mp} = GDP_{mp} + NFIA

.

3

Deduct depreciation (consumption of fixed capital) to determine Net National Product at market prices (

NNP_{mp}

)

NNP_{mp} = 775 - 40 = 735

billion

Net national aggregate equals gross national aggregate minus capital consumption.

4

Convert

NNP_{mp}

to Net National Product at factor cost (

NNP_{fc}

)

NNP_{fc} = 735 - 50 + 20 = 705

billion

Factor cost is obtained by deducting indirect taxes and adding subsidies (

NNP_{fc} = NNP_{mp} - \text{Indirect Taxes} + \text{Subsidies}

).

Key Concept

Expenditure Method of Measuring National Income and Aggregate Adjustments

Question 4896Question →

The supply function for a commodity is given by $Q_s = -20 + 5P$ , where $Q_s$ is the quantity supplied in units and $P$ is the price in Naira ( $\text{N}$ ). What is the quantity supplied when the price per unit is $\text{N}10$ ?

Show answer & explanation

Answer: 30

Answer

The quantity supplied when the price is

\text{N}10

is 30 units.

Substituting

P = 10

into the linear supply equation

Q_s = -20 + 5P

gives

Q_s = -20 + 5(10) = 30

units, directly reflecting the positive relationship between price and quantity supplied stated by the law of supply.

Step-by-Step Solution

1

Substitute the given price into the supply function

Q_s = -20 + 5(10)

The price

P

is specified as 10 Naira in the problem statement.

2

Perform the multiplication and addition

Q_s = -20 + 50 = 30

Evaluating the linear expression gives the total quantity supplied at price level 10.

Key Concept

Linear Supply Function and Quantity Supplied Calculation

Estimated Time:45s

Question 4897Question →

A cocoa farming cooperative in Ondo State receives an agricultural development grant of $\text{₦}5,000,000$ . The cooperative board evaluates two mutually exclusive projects: Option 1 is installing an automated processing plant estimated to generate $\text{₦}7,500,000$ in additional future revenue; Option 2 is constructing an irrigation canal system estimated to generate $\text{₦}6,800,000$ in additional future revenue. According to Lionel Robbins' definition of economics regarding scarcity and alternative uses, what constitutes the true economic cost of choosing to construct the irrigation canal system?

The

\text{₦}5,000,000

monetary outlay required to purchase materials and construct the irrigation canal system.

The foregone

\text{₦}7,500,000

additional revenue from the automated processing plant, representing the real alternative sacrifice made.

The net financial gain of

\text{₦}1,800,000

expected from the irrigation canal system after accounting for the initial grant.

An inward shift of the cooperative's production possibility curve resulting from funding allocation.

Show answer & explanation

Answer: The foregone $\text{₦}7,500,000$ additional revenue from the automated processing plant, representing the real alternative sacrifice made.

Answer

The foregone

\text{₦}7,500,000

additional revenue from the automated processing plant, which represents the next best alternative foregone (opportunity cost) when opting to construct the irrigation canal system.

Under Lord Lionel Robbins' formal definition, economics examines how rational agents allocate scarce means among competing ends. When two options are mutually exclusive, the true economic cost (opportunity cost) of selecting one project is the value of the next best alternative sacrificed. Choosing the irrigation canal means giving up the automated processing plant, which would have generated

\text{₦}7,500,000

in additional revenue.

Step-by-Step Solution

1

Analyze the core premise of economics according to Lionel Robbins.

Robbins defines economics as the science which studies human behavior as a relationship between ends and scarce means which have alternative uses.

Economic evaluation requires measuring decisions in terms of real alternative sacrifices rather than mere financial expenditures.

2

Identify the mutually exclusive options and their respective returns.

Option 1 yields

\text{₦}7,500,000

; Option 2 yields

\text{₦}6,800,000

. Selecting Option 2 means Option 1 must be sacrificed.

Opportunity cost is defined strictly as the value of the next best alternative foregone.

3

Differentiate opportunity cost from money cost and accounting profit.

The money cost is

\text{₦}5,000,000

, but the real economic opportunity cost of choosing the irrigation canal is the sacrificed return of

\text{₦}7,500,000

from the automated processing plant.

True economic evaluation measures scarcity by comparing sacrificed returns from alternative uses of resources.

Key Concept

Opportunity Cost and the Scope of Economics

Estimated Time:2m 0s

Question 4898Question →

Match each plant adaptive feature on the left with its corresponding physiological or morphological mechanism for environmental survival on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

The correct matches align each morphological structure with its functional role: Salt-secreting glands match active excretion of excess ionic solutes in saline soils; Stomata on upper epidermis match direct gaseous exchange in floating leaves; Aerenchyma tissue matches internal gas transport and buoyancy in aquatics; Reduced scale-like leaves match minimization of transpiration in arid habitats.

Each feature is paired with its exact ecological purpose: salt glands allow halophytes to survive high soil salinity by secreting salt; upper stomata enable floating hydrophytes to exchange gases without stomatal flooding; aerenchyma provides internal aeration in hypoxic aquatic soils; and reduced leaf surface area lowers transpirational water loss in xerophytes.

Step-by-Step Solution

1

Classify each adaptation according to its target environmental stress (salinity, waterlogging, floating aquatic life, or drought).

Salt glands correspond to halophytes; upper stomata and aerenchyma correspond to hydrophytes; reduced leaves correspond to xerophytes.

Environmental stresses dictate specific structural modifications.

2

Relate the structural modification to its primary physiological mechanism.

Excretion handles high osmolality, upper stomata maintain aeration on water surfaces, air spaces (aerenchyma) facilitate gas diffusion underwater, and reduced surface area conserves water.

Connecting form to function demonstrates understanding of ecological adaptations.

Key Concept

Morphological and Physiological Adaptations to Environments

Question 4899Question →

In long-run equilibrium, a profit-maximizing monopolist operating under conventional U-shaped cost curves will adjust its plant size to produce at the minimum point of its long-run average cost ( $LAC$ ) curve, thereby achieving productive efficiency.

True

False

Show answer & explanation

Answer: False

Answer

The statement is False. A profit-maximizing monopolist in long-run equilibrium operates at an output level below the capacity that minimizes long-run average cost, resulting in excess capacity and productive inefficiency.

Evaluating the statement as False is correct because a monopolist's profit-maximizing rule (

MR = MC

) under downward-sloping demand prevents output from reaching the minimum point of long-run average cost, causing productive inefficiency and excess capacity.

Step-by-Step Solution

1

Identify the monopolist's long-run profit-maximization condition.

The firm sets long-run marginal revenue equal to long-run marginal cost (

LMR = LMC

).

Profit maximization requires equalizing incremental revenue and incremental cost.

2

Analyze the relationship between Price (

P

), Marginal Revenue (

LMR

), and Average Cost (

LAC

).

Because the market demand curve slopes downward,

P > LMR = LMC

.

To sell additional units, the monopolist must lower the price on all units sold.

3

Determine the position of equilibrium on the

LAC

curve.

Equilibrium output occurs on the declining portion of the

LAC

curve, to the left of its minimum point.

Since

LMR

lies below the demand (

AR

) curve, the intersection

LMR = LMC

falls at an output level smaller than the scale that minimizes

LAC

.

4

Evaluate productive efficiency.

Productive efficiency is not achieved.

Productive efficiency requires producing at minimum

LAC

, which monopoly long-run equilibrium fails to attain.

Key Concept

Long-Run Monopoly Equilibrium and Productive Inefficiency (Excess Capacity)

Question 4900Question →

Match each lower invertebrate representative on the left with its corresponding structural or developmental feature on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Sycon pairs with flagellated collar cells (choanocytes); Obelia pairs with alternation of generations (metagenesis); Fasciola pairs with dorsoventrally flattened body and flame cells; Ancylostoma pairs with cylindrical unsegmented body possessing a pseudocoelom.

Each organism is correctly paired with the key anatomical innovation of its respective phylum: Sycon (Porifera) possesses choanocytes; Obelia (Coelenterata) displays metagenesis; Fasciola (Platyhelminthes) uses flame cells in a flattened body; and Ancylostoma (Nematoda) possesses a pseudocoelom.

Step-by-Step Solution

1

Identify the taxonomic phylum for each given organism

Sycon belongs to Porifera, Obelia to Coelenterata (Cnidaria), Fasciola to Platyhelminthes, and Ancylostoma to Nematoda.

Taxonomic classification determines the specific diagnostic tissue organization and body plan characteristics.

2

Match each organism to its unique cellular or anatomical diagnostic feature

Porifera (Sycon) have choanocytes; Coelenterata (Obelia) exhibit polyp-medusa metagenesis; Platyhelminthes (Fasciola) have flame cells; Nematoda (Ancylostoma) have a pseudocoelom.

These diagnostic structures represent distinct evolutionary features defining each of the four lower invertebrate phyla.

Key Concept

Diagnostic features of lower invertebrate phyla (Porifera, Coelenterata, Platyhelminthes, Nematoda)

Estimated Time:1m 0s

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept