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Question 4861Question →

In economic taxonomy, traditional economies resolve basic economic problems through non-market mechanisms. Match each operational aspect of a traditional economic system in Column A with its corresponding defining feature in Column B.

Click a left item, then click its matching right item

Show answer & explanation

Answer

The operational aspects of a traditional economy match their defining features as follows: Resource Allocation Basis matches ancestral customs and age-grade traditions; Primary Production Goal matches subsistence output aimed at immediate consumption; Mode of Transaction matches direct exchange of commodities without currency (barter); Asset Tenure System matches custodianship of productive land vested in the lineage or tribal chief.

Each feature accurately reflects the socio-economic realities of traditional systems: resource allocation is dictated by ancestral customs, production targets subsistence survival, commerce relies on trade by barter, and land control is vested in traditional custodians under customary law.

Step-by-Step Solution

Analyze the Resource Allocation Basis

Identify that traditional economies use heritage, caste, or age-grade customs to decide production questions, matching Ancestral customs and age-grade traditions.

Traditional economies lack price mechanisms or central planning bodies to allocate resources.

Analyze the Primary Production Goal

Identify that economic activity is subsistence-oriented rather than market-driven, matching Subsistence output aimed strictly at immediate household consumption.

Surplus accumulation and commercial profit maximization are rare due to limited technological innovation.

Analyze the Mode of Transaction

Identify that trade occurs via barter, matching Direct exchange of commodities without reliance on a standardized monetary medium of exchange.

Money is generally absent or underdeveloped in purely traditional societies.

Analyze the Asset Tenure System

Identify that land tenure is communal and managed by tribal authority, matching Custodianship of productive land vested in the lineage, clan, or tribal chief.

Customary land holding rights supersede individual private property deeds.

Key Concept

Key features and structural organization of a Traditional Economic System

Estimated Time:2m 0s

Question 4862Question →

The table below presents the total utility schedule for a consumer consuming successive units of commodity $Z$ :

Units of $Z$	Total Utility (utils)
1	18
2	32
3	42
4	48
5	50

If the market price of commodity $Z$ is $\mathbb{N}6$ per unit and $1\text{ util} = \mathbb{N}1$ , what is the consumer surplus at the equilibrium level of consumption?

\mathbb{N}24

\mathbb{N}48

\mathbb{N}20

\mathbb{N}12

Show answer & explanation

Answer: \mathbb{N}24

Answer

\mathbb{N}24

The option specifying $\mathbb{N}24$ is correct. Marginal utility per unit is derived as: Unit 1 = 18, Unit 2 = 14, Unit 3 = 10, Unit 4 = 6, Unit 5 = 2. With price $P_Z = \mathbb{N}6$, consumer equilibrium condition $MU_Z = P_Z$ is satisfied at 4 units of consumption. At 4 units, Total Utility is $\mathbb{N}48$ and Total Expenditure is $4 \times \mathbb{N}6 = \mathbb{N}24$. Consumer surplus is $48 - 24 = \mathbb{N}24$.

Step-by-Step Solution

Calculate Marginal Utility (MU) for each unit consumed

MU_1 = 18

MU_2 = 14

MU_3 = 10

MU_4 = 6

MU_5 = 2

Marginal utility is the change in total utility resulting from consuming one additional unit (

MU_n = TU_n - TU_{n-1}

Determine the consumer equilibrium quantity

Equilibrium occurs at 4 units because

MU_4 = \mathbb{N}6 = P_Z

Under cardinal utility analysis, a consumer maximizes utility for a single commodity when

MU = P

(in monetary terms).

Calculate Total Expenditure at equilibrium

\text{Total Expenditure} = 4 \times \mathbb{N}6 = \mathbb{N}24

Total expenditure is calculated by multiplying the equilibrium quantity by the unit price.

Compute Consumer Surplus

\text{Consumer Surplus} = \text{Total Utility} - \text{Total Expenditure} = \mathbb{N}48 - \mathbb{N}24 = \mathbb{N}24

Consumer surplus is the net monetary gain derived from consumption, calculated as the total utility minus total amount paid.

Key Concept

Cardinal Consumer Equilibrium and Consumer Surplus Calculation

Estimated Time:1m 30s

Question 4863Question →

Lower invertebrates display key evolutionary innovations in their body plans, cellular organizations, and functional systems. Pair each of the following invertebrate phyla on the left with its defining structural feature on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Porifera matches with presence of flagellated choanocytes; Coelenterata matches with specialized stinging nematocysts; Platyhelminthes matches with flame cells (protonephridia); Nematoda matches with fluid-filled pseudocoelom.

Each phylum is accurately matched with its primary evolutionary diagnostic feature: Porifera rely on choanocytes for feeding, Coelenterata utilize nematocysts for capture and defense, Platyhelminthes possess flame cells for osmoregulation, and Nematoda feature a pseudocoelom functioning as a hydrostatic skeleton.

Step-by-Step Solution

Analyze the characteristic features of Porifera

Porifera (sponges) possess specialized collar cells with flagella called choanocytes.

Choanocytes create water currents inside sponges to facilitate intracellular digestion.

Analyze the characteristic features of Coelenterata

Coelenterata (cnidarians) possess cnidocytes containing stinging capsules called nematocysts.

Nematocysts discharge toxins to immobilize prey and provide defense.

Analyze the characteristic features of Platyhelminthes

Platyhelminthes (flatworms) possess flame cells as their excretory units.

Flame cells harbor cilia that flicker like a flame to pump fluid out of the organism for osmoregulation.

Analyze the characteristic features of Nematoda

Nematoda (roundworms) feature an unsegmented body with a pseudocoelom.

The pseudocoelom is derived from the embryonic blastocoel and acts as a hydrostatic skeleton for movement.

Key Concept

Diagnostic anatomical structures and body cavity configurations of lower invertebrate phyla

Estimated Time:1m 30s

Question 4864Question →

In a given year, a country recorded a Nominal Gross Domestic Product (GDP) of $\$500\text{ billion}$ . The GDP deflator for the year was $125$ (with a base year index of $100$ ), and the total population was $50\text{ million}$ . What was the Real Per Capita Income of the country in dollars?

Show answer & explanation

Answer: 8000

Answer

The Real Per Capita Income of the country is $8,000.

To compute the Real Per Capita Income, Nominal GDP is first converted to Real GDP using the GDP deflator:

\frac{\$500\text{ billion}}{125} \times 100 = \$400\text{ billion}

. Dividing this real income figure by the population of

50\text{ million}

gives an average real per capita income of

\$8,000

Step-by-Step Solution

Deflate Nominal GDP to obtain Real GDP

Real GDP = $400 billion

Real GDP removes the inflationary effect measured by the GDP deflator.

Divide Real GDP by the population size

Real Per Capita Income = $8,000

Per capita real income measures average real economic output per person.

Key Concept

Real GDP and Per Capita Income Derivation

Estimated Time:1m 30s

Question 4865Question →

According to Charles Darwin's theory of natural selection, evolutionary changes occur in a specific logical sequence. Arrange the following processes in the correct chronological order in which natural selection acts upon a biological population.

Drag items to arrange them in the correct order

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Answer

The correct logical sequence of natural selection is: Overproduction leading to competition, pre-existing inherited variation, differential survival and reproduction of favored individuals, followed by population adaptation across generations.

Natural selection begins when overproduction of offspring causes competition for limited resources. Pre-existing inherited variations determine which individuals survive environmental pressure. Favorable traits allow greater reproductive success, increasing the trait's frequency in future generations.

Step-by-Step Solution

Identify the initiating condition in Darwin's model.

Overproduction of offspring occurs, leading to environmental resource limitation and competition.

Populations naturally produce excess offspring, creating a struggle for existence.

Determine the substrate upon which selection acts.

Inherited variation must already exist within the population.

Without pre-existing phenotypic variation, differential survival cannot select for specific traits.

Analyze the interaction between variation and environmental pressure.

Individuals with traits favored by the environment survive and reproduce at higher rates.

Differential reproduction ensures favorable alleles are passed to the next generation.

Establish the long-term population outcome.

The frequency of advantageous traits increases in subsequent generations.

Evolution by natural selection is defined as a change in population characteristics over time.

Key Concept

Darwinian Mechanism of Evolutionary Change by Natural Selection

Question 4866Question →

In the short run, a firm operating in a perfectly competitive market achieves profit maximization by expanding output up to the level where marginal cost ( $MC$ ) is equal to which of the following?

Marginal revenue (

MR

), which is also equal to market price (

P

)

Zero, to ensure total variable costs are kept to a minimum

Average fixed cost (

AFC

), at its lowest point

Total revenue (

TR

), to balance overall earnings with cost

Show answer & explanation

Answer: Marginal revenue ( $MR$ ), which is also equal to market price ( $P$ )

Answer

Marginal revenue (

MR

), which is also equal to market price (

P

)

Under perfect competition, each firm is a price taker facing a perfectly elastic demand curve where market price equals marginal revenue (

P = MR

). The universal rule for profit maximization requires producing output where marginal revenue equals marginal cost (

MR = MC

). Therefore, the firm maximizes short-run profit where marginal cost equals marginal revenue and price.

Step-by-Step Solution

Identify the firm's market structure

The firm operates under perfect competition where it is a price taker facing a perfectly elastic horizontal demand curve, making

P = AR = MR

Individual competitive firms cannot influence market price.

Apply the general profit maximization rule

Profit is maximized where marginal revenue equals marginal cost (

MR = MC

MR > MC

, producing an additional unit adds more to revenue than cost. If

MR < MC

, reducing production saves more cost than revenue lost.

Combine the conditions

The short-run output determination condition is

P = MR = MC

Since price equals marginal revenue for a competitive firm,

MC

must equal both

MR

and

P

Key Concept

Short-run Profit Maximization under Perfect Competition (

P = MR = MC

)

Estimated Time:45s

Question 4867Question →

Which economic policy in Nigeria involves re-organizing state-owned enterprises to operate as profit-oriented entities while retaining full government ownership?

Privatization

Commercialization

Indigenization

Import substitution

Show answer & explanation

Answer: Commercialization

Answer

Commercialization is the policy that restructures state-owned enterprises to run on commercial principles and generate profit while maintaining government ownership.

Commercialization is the economic reform policy where government-owned enterprises are restructured to operate profit-oriented and self-sustaining operations without transferring equity ownership to private entities.

Step-by-Step Solution

Identify the key requirement of the policy mentioned in the stem.

The policy requires public enterprises to operate on commercial terms and make profits while remaining fully owned by the state.

Understanding the distinction between ownership transfer and operational restructuring is essential for classifying Nigerian economic reform policies.

Evaluate the definition of Commercialization against the requirement.

Commercialization aims to increase efficiency and financial autonomy of public utilities without selling equity to private investors.

State-owned firms under commercialization operate like private commercial businesses but remain government assets.

Key Concept

Commercialization of Public Enterprises

Estimated Time:45s

Question 4868Question →

Match each economic commodity or scenario on the left with its corresponding classification of demand on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Petrol and motor vehicles match with Joint (Complementary) demand; Tea and coffee match with Competitive demand; Farm labour for agricultural production matches with Derived demand; Electricity used for lighting, cooking, and powering machinery matches with Composite demand.

Each commodity pair or scenario aligns with its defined classification of demand: petrol and cars are used together (joint demand), tea and coffee are substitutes (competitive demand), farm labour is needed for output production (derived demand), and electricity serves multiple functions (composite demand).

Step-by-Step Solution

Analyze 'Petrol and motor vehicles'

Since petrol and cars must be used together to provide transportation, they exhibit joint (complementary) demand.

Joint demand occurs when two or more goods are required together to satisfy a specific need.

Analyze 'Tea and coffee'

Tea and coffee serve as alternative goods satisfying similar beverage preferences, so they exhibit competitive demand.

Competitive demand occurs between substitute commodities where an increase in demand for one reduces demand for the other.

Analyze 'Farm labour for agricultural production'

Labour is demanded to produce crops rather than for direct consumption, representing derived demand.

Derived demand exists when the demand for a factor of production depends on the demand for the final output it helps produce.

Analyze 'Electricity used for lighting, cooking, and powering machinery'

Because electricity can be put to multiple different uses, it represents composite demand.

Composite demand refers to total demand for a product or resource that has multiple applications or uses.

Key Concept

Types of Demand (Joint, Competitive, Derived, and Composite)

Question 4869Question →

A software engineer in Lagos currently earns a salary of $₦500,000$ per month. She is considering quitting her job for one year to pursue one of two mutually exclusive opportunities:

- Opportunity X: Establish an independent tech startup requiring an initial capital investment of $₦3,000,000$ , which she must withdraw from her fixed deposit account currently yielding $12\%$ per annum interest. The startup is expected to generate $₦15,000,000$ in total revenue over the year, with total operating expenses (office rent, server infrastructure, and wages) amounting to $₦6,500,000$ .
- Opportunity Y: Work as an overseas remote contractor earning a net salary of $₦900,000$ per month with zero capital investment required.

Calculate, in Naira ( $₦$ ), the economic opportunity cost of choosing Opportunity X for the year.

Show answer & explanation

Answer: 11160000

Answer

The economic opportunity cost of choosing Opportunity X for the year is ₦11,160,000.

The economic opportunity cost of an action is defined as the total benefit of the next best alternative foregone. By choosing Opportunity X, the software engineer gives up Opportunity Y (worth ₦900,000 × 12 = ₦10,800,000) as well as the interest her ₦3,000,000 capital would have earned in the fixed deposit account (12% of ₦3,000,000 = ₦360,000). Together, the total sacrificed value of this highest-ranked foregone package equals ₦10,800,000 + ₦360,000 = ₦11,160,000.

Step-by-Step Solution

Calculate the annual income of all alternative employment options available during the year.

Current Job annual income = ₦500,000 × 12 = ₦6,000,000. Opportunity Y annual income = ₦900,000 × 12 = ₦10,800,000.

Opportunity cost evaluates the sacrifice made regarding alternative choices foregone.

Calculate the foregone interest earned if funds remain in the fixed deposit account.

Foregone annual interest = 12% of ₦3,000,000 = ₦360,000.

Selecting Opportunity Y or retaining her current job would leave the ₦3,000,000 intact in savings, earning 12% interest.

Determine the net value of the single best foregone alternative option.

Value of Next Best Alternative (Opportunity Y + Savings Interest) = ₦10,800,000 + ₦360,000 = ₦11,160,000.

Economic opportunity cost is defined as the total value of the highest-valued alternative option foregone.

Key Concept

Opportunity Cost as the Next Best Alternative Foregone

Estimated Time:3m 0s

Question 4870Question →

A major agricultural processing firm operates as the sole buyer of cocoa beans in a rural region. In profit-maximizing equilibrium, how do the prices paid to farmers and the quantity of cocoa purchased by this monopsonist compare to outcomes in a competitive market?

Both the price paid to farmers and the quantity purchased are lower.

The price paid to farmers is higher, but the quantity purchased is lower.

The price paid to farmers is lower, but the quantity purchased is higher.

Both the price paid to farmers and the quantity purchased are higher.

Show answer & explanation

Answer: Both the price paid to farmers and the quantity purchased are lower.

Answer

Both the price paid to farmers and the quantity purchased are lower in a monopsonistic market than in a competitive market.

Because a monopsonist is the sole buyer, its Marginal Factor Cost (

MFC

) exceeds the market supply price (

AFC

). To maximize profit, it equates

MFC

with Marginal Revenue Product (

MRP

), resulting in both a restricted quantity purchased and a depressed price paid to sellers compared to competitive market equilibrium.

Step-by-Step Solution

Identify the market structure and supply conditions.

The firm is a monopsony (sole buyer). It faces an upward-sloping supply curve for the input, meaning to buy more units, it must increase the price for all units bought.

Because the supply curve slopes upward, the Marginal Factor Cost (

MFC

) lies above the Supply curve (Average Factor Cost,

AFC

Determine the profit-maximizing purchasing decision.

The firm sets quantity where

MFC = MRP

(Marginal Revenue Product), purchasing quantity

Q_m

, which is lower than competitive quantity

Q_c

(where Supply =

MRP

Profit maximization requires equating the extra cost of hiring/buying one more unit with the extra revenue generated by that unit.

Determine the price paid to suppliers.

The firm pays the price

P_m

indicated on the supply curve for quantity

Q_m

, which is lower than the competitive equilibrium price

P_c

The monopsonist uses its market power to pay the lowest price suppliers are willing to accept for quantity

Q_m

Key Concept

Monopsony Equilibrium and Factor Price Depresssion

Estimated Time:1m 0s

Question 4871Question →

A consumer obtains an average utility ( $AU$ ) of $15$ utils from consuming $4$ units of bottled water. When the $5^{\text{th}}$ unit is consumed, the marginal utility ( $MU$ ) derived is $25$ utils. If consuming the $6^{\text{th}}$ unit brings the consumer's total utility ( $TU$ ) to $96$ utils, what is the average utility ( $AU$ ) per unit, in utils, when $6$ units are consumed?

Show answer & explanation

Answer: 16

Answer

The average utility per unit when 6 units are consumed is 16 utils.

To find the average utility after 6 units, determine total utility at 4 units (

15 \times 4 = 60

utils). Adding the marginal utility of the 5th unit (

25

utils) gives a total utility of

85

utils for 5 units. Since total utility for 6 units is given as

96

utils, dividing by quantity (

96 / 6

) yields an average utility of

16

utils.

Step-by-Step Solution

Calculate Total Utility for 4 units (

TU_4

)

TU_4 = 60

utils

Total utility is calculated by multiplying average utility by the quantity consumed:

TU_4 = AU_4 \times 4 = 15 \times 4 = 60

utils.

Calculate Total Utility for 5 units (

TU_5

)

TU_5 = 85

utils

Total utility of 5 units equals total utility of 4 units plus the marginal utility of the 5th unit:

TU_5 = TU_4 + MU_5 = 60 + 25 = 85

utils.

Identify Total Utility for 6 units (

TU_6

)

TU_6 = 96

utils

The total utility after consuming 6 units is given directly in the problem description as 96 utils.

Calculate Average Utility for 6 units (

AU_6

)

AU_6 = 16

utils

Average utility is calculated by dividing total utility by total units consumed:

AU_6 = \frac{TU_6}{6} = \frac{96}{6} = 16

utils.

Key Concept

Mathematical interrelationships between Total Utility (TU), Average Utility (AU), and Marginal Utility (MU)

Question 4872Question →

Match each public expenditure concept or theoretical model on the left with its corresponding operational definition or economic characteristic on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Wagner's Law matches the concept that public expenditure grows continuously and faster than national income during industrialization. The Peacock-Wiseman Displacement Effect matches step-like increases in public spending caused by social crises. Recurrent Expenditure matches ongoing administrative operational expenses such as wages. Transfer Payments match government redistributive spending where no current economic goods or services are received.

Each concept correctly aligns with its theoretical formulation or public accounting definition. Wagner's Law describes continuous spending expansion exceeding GDP growth, Peacock-Wiseman explains crisis-induced step-wise displacement, recurrent expenditure covers routine operational running costs, and transfer payments represent unrequited redistributive outlays.

Step-by-Step Solution

Identify long-term structural theories of public expenditure growth

Wagner's Law specifies continuous, organic expansion of the public sector relative to GDP as society industrializes.

It explains the income elasticity of demand for public goods during development.

Differentiate emergency or shock-driven spending growth hypotheses

The Peacock-Wiseman Hypothesis focuses on structural shifts ('displacement effect') where emergency situations ratchet up public expenditure levels permanently.

Public spending stays elevated after socio-economic crises resolve.

Classify government budget expenditures based on durability and output involvement

Recurrent spending covers operational running costs within the year, while transfer payments involve redistribution without corresponding factor output.

Transfer payments do not contribute directly to gross domestic product calculations.

Key Concept

Public Expenditure Classification and Growth Theories

Question 4873Question →

A consumer purchasing two goods, $X$ and $Y$ , attains equilibrium when the marginal utility of Good $X$ ( $MU_x$ ) is $40$ utils and its price ( $P_x$ ) is $\text{₦}10$ . If the price of Good $Y$ ( $P_y$ ) is $\text{₦}5$ , what is the marginal utility of Good $Y$ ( $MU_y$ ) in utils at consumer equilibrium?

Show answer & explanation

Answer: 20 utils; 20; 20utils

Answer

The marginal utility of Good

Y

at consumer equilibrium is 20 utils.

Under cardinal utility analysis, consumer equilibrium for two commodities is achieved when the ratio of marginal utility to price is equal for both commodities (

\frac{MU_x}{P_x} = \frac{MU_y}{P_y}

). Substituting

MU_x = 40

P_x = 10

, and

P_y = 5

gives

\frac{40}{10} = \frac{MU_y}{5}

, which simplifies to

4 = \frac{MU_y}{5}

. Solving for

MU_y

gives

20

utils.

Step-by-Step Solution

State the equimarginal condition for consumer equilibrium when consuming two goods.

\frac{MU_x}{P_x} = \frac{MU_y}{P_y}

According to cardinal utility analysis, a consumer maximizes utility when the marginal utility per monetary unit spent is equal across all commodities.

Substitute the given values (

MU_x = 40

P_x = 10

P_y = 5

) into the formula.

\frac{40}{10} = \frac{MU_y}{5}

Substituting the known parameters sets up an algebraic equation for the unknown marginal utility of Good

Y

Solve the equation for

MU_y

4 = \frac{MU_y}{5} \implies MU_y = 4 \times 5 = 20\text{ utils}

Multiplying the marginal utility per naira spent (4 utils/naira) by the price of Good

Y

(₦5) gives the marginal utility of Good

Y

Key Concept

Equimarginal Principle of Consumer Equilibrium

Estimated Time:1m 30s

Question 4874Question →

Match each fiscal policy scenario or tool with its corresponding economic stabilization action.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Expansionary fiscal policy during a recession pairs with reducing taxes and expanding spending; Contractionary fiscal policy during inflation pairs with increasing taxes and curtailing spending; Automatic fiscal stabilizers during expansions pair with automatic tax receipt growth under progressive taxation; Discretionary deficit financing pairs with intentional spending funded by borrowing.

Expansionary measures increase aggregate demand during downturns, contractionary measures suppress excess demand during inflationary periods, automatic stabilizers function continuously without legislative intervention, and discretionary deficit spending relies on intentional government borrowing for investment.

Step-by-Step Solution

Analyze economic recession requirements

Recessions require stimulating aggregate demand through fiscal stimulus, consisting of lower tax rates and boosted public expenditure.

Increasing disposable income and public outlay offsets output contraction.

Analyze demand-pull inflation requirements

Excess aggregate demand causing inflation must be dampened by withdrawing money from circulation via higher taxation and reduced spending.

Lower consumer disposable income and public spending bring price levels toward stability.

Distinguish built-in stabilizers from discretionary policy

Built-in stabilizers operate automatically through mechanisms such as progressive taxation without legislative delays, whereas discretionary deficit financing requires explicit policy decisions to borrow and spend.

Automatic stabilizers adjust continuously with economic cycles, while discretionary policy represents targeted intervention.

Key Concept

Fiscal Policy Tools and Economic Stabilization

Question 4875Question →

For the Haber process reaction represented by the thermochemical equation:

N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g) \quad \Delta H = -92\text{ kJ mol}^{-1}

Match each applied stress condition on the left with its corresponding effect on the equilibrium system on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Increasing temperature matches shifting equilibrium to the left (decreasing

NH_3

yield); Increasing total pressure matches shifting equilibrium to the right (increasing

NH_3

yield); Adding iron catalyst matches increasing rates equally without shifting position; Adding argon gas at constant volume matches having no effect on partial pressures or equilibrium position.

Each stress condition matches its specific thermodynamic or kinetic outcome according to Le Chatelier's principle: heating an exothermic reaction favors the reverse endothermic direction; increasing pressure favors the side with fewer gas moles (products); adding a catalyst accelerates both reaction directions equally; and adding inert gas at constant volume leaves partial pressures unchanged.

Step-by-Step Solution

Analyze temperature perturbation using exothermic enthalpy data

The forward reaction releases heat (\Delta H = -92\text{ kJ mol}^{-1}). Heating shifts equilibrium in the heat-absorbing (endothermic/reverse) direction.

Le Chatelier's principle predicts the system counteracts temperature elevation by favoring the endothermic reaction.

Analyze pressure perturbation using stoichiometric gas coefficients

Reactants contain 4 moles of gas (

1N_2 + 3H_2

) while products contain 2 moles (

2NH_3

). Increased pressure shifts equilibrium toward fewer gas moles.

Decreasing volume increases gas pressure, so the system relieves pressure by forming fewer gaseous molecules.

Determine catalyst effect on dynamic equilibrium

The iron catalyst accelerates both forward and reverse rates equally.

Catalysts alter the reaction mechanism to lower activation energy equally in both directions, leaving equilibrium composition unchanged.

Determine inert gas effect at constant volume

Adding argon at constant volume does not change concentrations or partial pressures of

N_2

H_2

, or

NH_3

Equilibrium position depends strictly on partial pressures of reacting species, which remain constant.

Key Concept

Le Chatelier's Principle (effects of temperature, pressure, catalysts, and inert gas additions)

Estimated Time:1m 30s

Question 4876Question →

Freshwater teleost fishes live in an environment that is hypoosmotic relative to their internal body fluids, leading to continuous passive influx of water and loss of essential salts. Which of the following physiological adaptations enables these fishes to maintain osmotic homeostasis?

Excreting large volumes of dilute urine while actively absorbing salts through gill chloride cells

Drinking large quantities of water while actively excreting salt ions through rectal glands

Excreting nitrogenous waste as insoluble uric acid paste to prevent water loss

Eliminating excess salts through Malpighian tubules while reducing renal filtration

Show answer & explanation

Answer: Excreting large volumes of dilute urine while actively absorbing salts through gill chloride cells

Answer

Excreting large volumes of dilute urine while actively absorbing salts through gill chloride cells

Freshwater teleost fishes are hypertonic to their surrounding habitat. Water constantly enters their tissues by osmosis, while electrolytes are lost by diffusion. To maintain osmoregulatory balance, their kidneys produce a large volume of dilute urine to void excess water, and specialized epithelial cells (chloride cells) in their gills actively absorb sodium and chloride ions from the dilute water into the bloodstream.

Step-by-Step Solution

Analyze the environmental osmotic pressure acting on freshwater teleost fishes.

The surrounding freshwater is hypoosmotic (lower solute concentration) than the fish's body fluids, causing water to continuously enter passively across the gills and skin while body salts diffuse outward.

Determining the osmotic gradient is necessary to identify the corrective physiological mechanism.

Identify the required physiological adjustments to handle water influx and salt loss.

The fish must continuously expel excess water without losing too many salts, while actively acquiring replacement ions from dilute surroundings.

Maintaining internal hydromineral balance requires coordinated kidney and gill function.

Match the required adjustments to specific vertebrate organs and cellular adaptations.

Large renal glomeruli produce large volumes of dilute urine to void water, and specialized chloride cells in the gill epithelium actively transport sodium and chloride ions into the blood against a concentration gradient.

This dual mechanism resolves both osmotic water loading and ionic dilution.

Key Concept

Physiological Osmoregulation in Freshwater Teleost Fishes

Question 4877Question →

Arrange the following sequential steps involved in the laboratory preparation and isolation of soap (saponification) from vegetable oil in the correct chronological order from first to last:

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct order of steps for the preparation and isolation of soap is: first, refluxing the vegetable oil with concentrated sodium hydroxide (saponification); second, adding concentrated sodium chloride solution (salting out); third, filtering the mixture to separate the solid soap curd; and fourth, washing the solid soap with cold distilled water to remove impurities.

Saponification begins by refluxing vegetable oil (a triglyceride ester) with concentrated sodium hydroxide, hydrolyzing the ester links to yield sodium alkanoates (soap) and glycerol. Next, concentrated sodium chloride solution is added (salting out) to precipitate the soap by decreasing its solubility. The mixture is then filtered to isolate the solid soap curd from the liquid filtrate, and finally, the solid residue is washed with cold distilled water to remove excess sodium hydroxide.

Step-by-Step Solution

Reflux vegetable oil with aqueous sodium hydroxide solution.

Complete alkaline hydrolysis of the triester (triglyceride) into glycerol and sodium alkanoates (soap).

Base-catalyzed ester hydrolysis is required to break down the vegetable oil into fatty acid sodium salts.

Add concentrated sodium chloride solution (brine) to the reaction mixture.

Precipitation of sodium alkanoate (soap) as a floating curd.

Increasing the concentration of sodium ions forces the soap salt out of solution due to the common-ion effect and reduced solubility.

Filter the mixture using a funnel and filter paper.

Crude solid soap is retained on the filter paper while glycerol and brine pass through as filtrate.

Filtration separates the insoluble soap precipitate from the soluble glycerol byproduct.

Rinse the collected soap residue with cold water.

Purified soap free from unreacted sodium hydroxide and salt.

Cold water dissolves remaining surface impurities without dissolving significant amounts of the solid soap.

Key Concept

Saponification process and salting out of soap

Estimated Time:1m 30s

Question 4878Question →

Arrange the following physiological and mechanical events in the correct sequential order during the peristaltic movement of an earthworm, starting from the initial elongation of anterior segments.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct sequence of peristaltic locomotion in an earthworm is: contraction of circular muscles causing anterior elongation, protrusion and anchoring of anterior chaetae into the substrate, contraction of longitudinal muscles causing body shortening, and retraction of posterior chaetae allowing rear displacement.

In earthworm hydrostatic locomotion, movement relies on alternating waves of antagonistic muscle contraction acting against fluid-filled coelomic compartments. Elongation is initiated by circular muscle contraction. Next, anterior chaetae anchor the extended front to the ground. Then, longitudinal muscles contract to shorten the segments and pull the posterior body forward while posterior chaetae retract to reduce drag.

Step-by-Step Solution

Identify the initial muscular contraction responsible for body elongation.

Circular muscles contract while longitudinal muscles relax, extending the anterior body forward.

Hydrostatic pressure pushes coelomic fluid forward when circular muscles exert compressive force on the segment walls.

Determine the anchoring step following elongation.

Anterior chaetae protrude and anchor into the substrate.

Anchoring prevents backward slippage when the pulling force is subsequently generated.

Identify the muscular contraction responsible for pulling the rear body forward.

Longitudinal muscles contract while circular muscles relax in the anterior region.

Longitudinal muscle contraction shortens and swells the segments, drawing the unanchored rear segments forward.

Identify the release step at the posterior end.

Posterior chaetae retract from the soil.

Releasing posterior friction enables the hind portion of the organism to slide forward freely toward the anchored front.

Key Concept

Hydrostatic skeleton and antagonistic muscle action in annelid peristaltic locomotion

Estimated Time:1m 0s

Question 4879Question →

A commercial bank receives an initial cash deposit of ₦50,000. If the central bank specifies a cash reserve ratio of 20%, what is the total amount of deposits created in the banking system?

Show answer & explanation

Answer: 250000

Answer

The total amount of deposits created in the banking system is ₦250,000.

The total amount of deposits created across the commercial banking system is calculated using the formula

\text{Total Deposit} = \frac{\text{Initial Deposit}}{\text{Cash Reserve Ratio}}

. Substituting the given values gives

\frac{₦50,000}{0.20} = ₦250,000

Step-by-Step Solution

Identify the given initial deposit and cash reserve ratio.

Initial Deposit = ₦50,000; Cash Reserve Ratio (CRR) =

20\% = 0.20

These parameters are required to compute credit expansion.

Apply the total credit creation formula.

\text{Total Deposit Expansion} = \frac{\text{Initial Deposit}}{\text{Cash Reserve Ratio}}

The commercial banking system creates secondary deposits equal to the initial primary deposit divided by the cash reserve ratio.

Perform the numerical calculation.

\text{Total Deposit Expansion} = \frac{50,000}{0.20} = 250,000

Dividing ₦50,000 by 0.20 yields ₦250,000.

Key Concept

Credit Creation and Total Deposit Expansion

Question 4880Question →

An agro-industrial processing firm in West Africa assigns workers exclusively to narrow, repetitive tasks: one crew sorts raw cocoa beans, another manages roasting, and a third operates the extraction press. Following an upgrade to fully automated bean-sorting technology, the manual sorting staff face severe unemployment because their highly specialized skills cannot easily be transferred to other technical roles within the enterprise. Which major drawback of division of labor is directly demonstrated by this situation?

Occupational immobility of labor due to extreme skill narrowness

Diminishing marginal returns resulting from over-utilization of fixed capital inputs

Inefficiencies arising from the geographical localization of manufacturing industries

Loss of absolute cost advantage in foreign export markets

Show answer & explanation

Answer: Occupational immobility of labor due to extreme skill narrowness

Answer

Occupational immobility of labor due to extreme skill narrowness

Extreme division of labor forces workers to perform single repetitive tasks, leading to loss of overall craftsmanship and versatility. When technology renders a specific task redundant, these workers suffer from occupational immobility because their skills are too specialized to be easily repurposed elsewhere in the economy or firm.

Step-by-Step Solution

Analyze the production process scenario

Workers perform single, narrow sub-tasks (manual sorting) repeatedly in an assembly process.

This establishes extreme division of labor.

Evaluate the impact of automation on the specialized workforce

The manual sorters are displaced and cannot adapt to other roles because they lack broader technical training.

Specialization reduces versatility across different occupations or job functions.

Identify the corresponding economic concept

The inability of workers to switch jobs easily represents occupational immobility of labor.

Occupational immobility is a primary structural disadvantage of specialization.

Key Concept

Disadvantages of Division of Labor: Occupational Immobility of Labor

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