All practice questions

The following passage is from an essay about paleontological history.

In the early nineteenth century, fossil collector Mary Anning made groundbreaking discoveries along the cliffs of Lyme Regis. She frequently sent fossil specimens and detailed anatomical drawings to geologist William Buckland. They helped shape early scientific understanding of prehistoric life, though Anning's contributions were rarely credited.

Which of the following options is the best replacement for the underlined word?

### Younger Dryas Cooling

The Younger Dryas was a period of abrupt global cooling that occurred approximately $12{}900$ years ago. Scientists debate the primary cause of this cooling event.

Hypothesis 1
A massive release of freshwater from Lake Agassiz flowed into the North Atlantic Ocean. Because freshwater is less dense than saltwater, this influx capped the warm ocean currents of the thermohaline circulation, halting the transport of heat to the Northern Hemisphere and triggering rapid cooling.

Hypothesis 2
A large comet entered Earth's atmosphere and exploded over North America. The heat and shockwaves from this impact event destabilized the Laurentide Ice Sheet and ignited widespread wildfires, throwing immense dust and soot into the atmosphere that blocked sunlight and caused global cooling.

New Evidence
Researchers analyze marine sediment cores and find that the influx of freshwater into the North Atlantic Ocean—indicated by a distinct drop in salinity and freshwater-associated oxygen isotopes (such as $\delta^{18}\text{O}$)—occurred approximately $100$ to $150$ years *after* Northern Hemisphere temperatures had already rapidly dropped.

Based on this information, how does the new evidence affect the two hypotheses?

In the early days of aviation, pilots relied heavily on visual landmarks and basic compasses to navigate. Because they lacked modern radar systems, these early aviators regularly scanned the horizon, watched for changes in the weather, and they are adjusting their flight paths accordingly. These careful observations were critical to ensuring a safe arrival at their destinations.

Which choice best maintains a consistent grammatical construction in the underlined portion of the sentence?

The geologist who's research focused on seismic activity discovered a new fault line near the mountain range.

Which choice is the correct word to use in the underlined portion of the sentence?

A student conducts three trials to investigate the mathematical relationships between voltage ($V$), current ($I$), resistance ($R$), and electric power ($P$) in a DC circuit. The data collected from these trials are shown in the tables below:

Based on the tables, match each trial to the mathematical relationship that best describes the variables in that trial.

In the sentence, 'Of the two scientific models presented at the conference, the first one is the most comprehensive,' the underlined word 'most' is used correctly.

Fill in the blank with the correct form of the verb *analyze* to maintain a consistent grammatical construction and avoid an inappropriate shift in verb tense.

### Racetrack Playa Sailing Stones

Racetrack Playa is a dry lakebed in Death Valley where rocks, ranging in weight from a few ounces to hundreds of pounds, slide across the flat clay surface, leaving long tracks behind them. No one has observed the rocks in motion in person, leading to several hypotheses.

Scientist 1
The stones are moved by the direct action of strong winds on the stones themselves. During winter storms, brief periods of rain cover the playa with a thin layer of water, transforming the clay surface into an extremely slick mud. When wind speeds exceed $75\text{ km/h}$, the force of the wind overcoming the minimal friction of the wet clay is sufficient to push the stones forward. The direction and shape of the tracks are entirely determined by the changing directions of these high-velocity wind gusts.

Scientist 2
Wind alone cannot push heavy stones across wet clay, even with reduced friction. Instead, water on the playa must freeze into thin, floating ice sheets during cold winter nights. These ice sheets lock the stones in place. As the ice begins to melt and break up under sunny conditions, strong winds push the large sheets of ice. Because these ice sheets have a massive surface area, the wind exerts a force large enough to drag the ice sheets, along with the embedded stones, across the slippery mud below.

Scientist 3
The movements are initiated by localized atmospheric vortices, or dust devils, that form over the playa. These vortices create sudden, rotating low-pressure centers directly above the rocks. The drop in pressure reduces the normal force of the rock on the muddy playa surface, effectively making it lighter, while the high rotational wind speeds of the vortex spin and propel the rock forward. Once the initial friction is overcome, the rock slides along the slick clay, guided by the vortex's path.

Based on the hypotheses presented, which of the following statements best describes the core claim of Scientist 2 regarding how wind is able to move the stones?

Aeroponics is a soil-free cultivation method that suspends plant roots in the air, where they are periodically misted with nutrient-rich water. By eliminating the need for soil or growing media, this technique drastically reduces water consumption while accelerating plant growth. Traditional farming, however, remains more cost-effective for large-scale grains, urban vertical farms are increasingly adopting aeroponics for high-value leafy greens.

Which of the following options best replaces the underlined portion of the passage?

Students conducted two experiments to study the decomposition of hydrogen peroxide ($H_2O_2$) into water and oxygen gas ($O_2$) in the presence of a yeast catalyst suspension.

Experiment 1
A test tube was filled with $10\text{ mL}$ of $3\%$ $H_2O_2$ solution. A yeast suspension with a concentration of $1.0\text{ g/L}$ was prepared. The students added $1\text{ mL}$ of the yeast suspension to the test tube at a temperature of $25^\circ\text{C}$ and measured the volume of $O_2$ gas produced over $5\text{ minutes}$. This procedure was repeated at temperatures of $35^\circ\text{C}$, $45^\circ\text{C}$, and $55^\circ\text{C}$.

Experiment 2
Using the same apparatus at a constant temperature of $35^\circ\text{C}$, the students added $1\text{ mL}$ of yeast suspensions of varying concentrations ($0.5\text{ g/L}$, $1.0\text{ g/L}$, $1.5\text{ g/L}$, and $2.0\text{ g/L}$) to separate test tubes, each containing $10\text{ mL}$ of $3\%$ $H_2O_2$ solution. The volume of $O_2$ gas produced was measured over $5\text{ minutes}$.

Based on the experimental designs described, is the statement that the concentration of the yeast suspension served as the independent variable in Experiment 1 and as a controlled variable in Experiment 2 true or false?

Complete the sentence by filling in the blanks with the correct words from the frequently confused pair 'elicit' and 'illicit'.

Although the dental wear patterns of the Tyrannosaurus rex were more pronounced then a Triceratops, both species exhibited specialized adaptations that suited their respective diets.

Which of the following choices best corrects the underlined portion of the sentence?

For decades, historians believed that the development of agriculture was the primary catalyst for the rise of complex human civilizations. The discovery of Göbekli Tepe in modern-day Turkey, however, challenged this conventional narrative. Dated to around 9600 BCE, this massive stone temple complex predates the earliest known agricultural settlements in the region. [1] In contrast, researchers now hypothesize that the desire to gather for religious rituals may have actually driven the transition to farming, rather than the other way around.

Which choice provides the most logical transition between the two sentences?

In 1910, astronomers eagerly awaited the arrival of Halley's Comet, which was passing close to Earth. While researchers prepared telescopes to analyze the comet's composition, the general public focused on reports of toxic cyanogen gas in its tail. Although scientists tried to reassure people that the gas was far too thin to cause harm, it led to widespread panic and the hoarding of 'comet pills.'

Which choice is the best replacement for the underlined word?

### Prebiotic Chemistry and the Origin of Life

Scientists debate the mechanisms by which the first living systems emerged on early Earth.

Hypothesis 1
The first life-like systems began with self-replicating ribonucleic acid ($RNA$) molecules. These $RNA$ molecules functioned both as the genetic blueprint and as catalysts (ribozymes) that drove the earliest metabolic reactions. Simple metabolic networks and proteins only evolved later under the control and direction of these self-replicating $RNA$ molecules.

Hypothesis 2
Life began as self-sustaining, organized networks of chemical reactions (metabolism) catalyzed by inorganic mineral surfaces, such as iron-sulfur minerals found at deep-sea hydrothermal vents. Genetic molecules like $RNA$ and $DNA$ did not initiate life; rather, they emerged much later as products of these metabolic networks to store genetic information and stabilize the pre-existing reactions.

New Evidence
Researchers simulated a hydrothermal vent environment containing iron-sulfur minerals but completely lacking any organic polymers (such as $RNA$ or proteins). When carbon dioxide ($CO_2$) and hydrogen ($H_2$) gases were introduced, the mineral surfaces catalyzed a self-sustaining cycle that continuously produced simple organic molecules, including amino acids and carboxylic acids.

Which of the following statements best describes how this new evidence impacts the two hypotheses?

The following passage contains an underlined portion.

Mycorrhizal fungi establish vast underground networks, they link the roots of different plants to facilitate nutrient exchange. Through these fungal threads, trees can share carbon, water, and warning signals about pests; therefore, the network acts as a primitive communication system. This mutualistic relationship, which is vital for forest health, sustains entire ecosystems.

Which of the following choices best corrects the underlined portion of the passage?

### Models of the Hawaiian-Emperor Seamount Chain Formation

The Hawaiian-Emperor seamount chain is a long line of volcanoes and seamounts stretching approximately $6,000\text{ km}$ across the Pacific Ocean. The ages of these volcanoes increase progressively from $0\text{ million years}$ (active volcanoes in the southeast) to over $80\text{ million years}$ (eroded seamounts in the northwest). Scientists propose two models to explain the formation of this volcanic chain.

#### Model 1
A stationary mantle plume—a localized upwelling of exceptionally hot rock—originates deep within Earth's mantle near the core-mantle boundary. As the Pacific Plate moves slowly northwestward over this fixed hotspot, magma penetrates the lithosphere, forming a series of volcanoes. The older volcanoes are carried away from the hotspot, becoming inactive and eroded over time, while new volcanoes form directly above the plume. The volcanic activity is driven solely by deep-seated thermal anomalies that are independent of plate boundaries or local tectonic stresses.

#### Model 2
The volcanic chain is caused by propagating fractures in the Pacific Plate itself, created by changes in plate motion and regional tectonic stresses. The Pacific Plate experiences tensional stress that causes the lithosphere to crack. As these cracks propagate southeastward over time, they depressurize the shallow mantle directly underneath, causing localized melting (decompression melting). Magma rises through the newly formed fractures to build volcanoes. The age progression is a result of the gradual propagation of the fractures, and no deep-seated, stationary mantle hotspot is involved.

According to the descriptions of the two models, Model 1 and Model 2 disagree on which of the following points?

To avoid a dangling modifier, complete the sentence by filling in the blank with either the pronoun 'I' or the noun phrase 'the telescope' to establish a logical subject for the introductory phrase:

Which words correctly complete the comparative and superlative structures in the passage below? Complete the passage by writing the correct word or phrase in each blank.

The following sentence contains an underlined portion: 'While exploring the depths of the local cave system, the geologist discovered a smooth, dark, limestone, shelf that had been carved by water over thousands of years.' Which choice represents the correct punctuation for the underlined portion?