ACT Success - Science - Practice #5

There are several passages in this test. Each passage is followed by several questions. After reading a passage, choose the best answer to each question. You may refer to the passages as often as necessary. You are NOT permitted to use a calculator on this test.

This study examined how resistance exercise affects free testosterone and total testosterone levels in two groups: MR (male participants) and FR (female participants). Participants performed a sequence of resistance exercises, including leg press (2 sets), leg press (4 sets), squat (2 sets), and knee extension (2 sets). Blood samples were taken before exercise, after each set, and during recovery (15 and 30 minutes post-exercise). The concentrations of free testosterone and total testosterone were measured in nanomoles per liter (nmol/L) and recorded for both groups. The results suggest that resistance exercise elevates both free and total testosterone levels temporarily, with differences between male and female participants.

If a follow-up experiment was conducted with an additional exercise set added to the squat exercise, how would you expect free testosterone levels to change for the MR group during this additional set, based on the trends observed?

Considering the data for FR, what can be inferred about the relationship between the volume of resistance exercise (number of sets) and total testosterone levels during recovery?

This study investigated how two animals—the tree shrew and the summit rat—deposit scat (waste) inside and outside pitcher plants over time, potentially influencing nutrient availability for the plants. Researchers observed and recorded the daily rate of scat deposits (per pitcher per day) for tree shrews and summit rats. Separate graphs track scat deposits inside the pitchers and outside the pitchers for each species over a 40-day period. The data suggest that both species contribute nutrients in different patterns, with tree shrews being more consistent in their deposits, particularly inside the pitchers.

Based on the trends in the data, if the summit rat population decreased significantly, what would likely be the long-term impact on nutrient availability for the pitcher plants?

If researchers discovered that pitcher plants located farther from summit rat habitats had slower growth rates, which hypothesis would be most consistent with this observation?

This experiment explored how individuals perceive the rotation direction of their own hands during clockwise (CW) and counterclockwise (CC) movements. Participants were asked to rotate their hands in both directions while researchers measured the actual angle of rotation and the angle perceived by participants. Measurements were taken at 10-second intervals across five phases for both CW and CC rotations. The results indicate a discrepancy between actual and perceived hand rotation angles, with participants overestimating their rotation in both directions.

If participants were asked to perform a larger rotation angle in the CW direction, which phase would most likely show the greatest discrepancy between actual and perceived angles, and why?

Based on the observed data, if participants were trained to focus on accurately perceiving their hand's rotation, what trend would likely appear in a repeated test after training?

A team of scientists tested the effects of different soil pH levels on the growth of two plant species, Species X and Species Y, over a 30-day period. If a different soil additive were applied, lowering the pH to 3, what would be the most likely outcome for both plant species?

In an experiment, a physicist measures the rate of chemical reactions at different temperatures, finding that reaction rates double every 10°C increase in temperature starting from 20°C. If the reaction rate is 8 units per minute at 30°C, what would the expected reaction rate be at 50°C?

A biologist observes that enzyme activity for Enzyme Q is optimal at pH 7. Below pH 4 or above pH 10, Enzyme Q becomes inactive. If the biologist gradually increased the pH from 4 to 8, at which pH range would Enzyme Q’s activity most likely start to rise significantly?

In a study on bacterial growth, bacteria were grown in dishes with different sugar concentrations. Bacterial growth increased with sugar concentration until reaching 20% sugar, where growth plateaued. Beyond 30%, growth began to decline.

A researcher measures the concentration of dissolved oxygen in a lake at various depths. She finds that oxygen concentration decreases significantly as depth increases, reaching near zero at 20 meters. What would most likely happen to the fish population at depths greater than 20 meters?

An ecologist observes that a particular species of grass grows faster in soil with a higher concentration of nitrates. When grown in nitrate-rich soil, the grass reaches its maximum growth rate. However, too much nitrate causes leaf browning and stunted growth.

A chemist performs an experiment to determine how changing the concentration of reactant A affects the rate of a reaction. Doubling the concentration of A causes the reaction rate to quadruple, while tripling the concentration of A causes the reaction rate to increase ninefold. Which of the following best describes the relationship between the concentration of A and the reaction rate?