ACT Success - Science - Practice #3

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 graph represents the results of a study examining the historical correlation between solar radiation intensity and methane (CH4) concentration in Earth’s atmosphere over the last 10,000 years. Experimental Setup and Data Collection: Scientists reconstructed past solar radiation intensity and atmospheric methane levels by analyzing geological and ice core samples, which contain trapped air bubbles preserving ancient atmospheric compositions. The solar radiation intensity data were likely derived from climate proxies, such as changes in isotopic composition, which correlate with historical solar activity. Methane concentration data came from direct measurement of gas content in the ice cores. Findings: The dashed line shows solar radiation intensity, which is measured in watts per square meter (W/m²) and is displayed on the left y-axis. The solid line represents methane concentration in parts per billion (ppb) on the right y-axis. The x-axis spans from 10,000 years ago to the present. As the data show, solar radiation intensity has generally decreased over the last 10,000 years, while methane concentration has fluctuated but overall increased, with a particularly sharp rise in recent centuries. This suggests potential links between solar activity, climate patterns, and methane levels, possibly influenced by both natural processes and recent human activity.

Which of the following methods would most likely have been used to obtain the methane concentration data in this study?

According to the figure, what trend is observed in solar radiation intensity over the past 10,000 years?

The sharp increase in methane concentration in recent times may be attributed to which of the following factors?

This figure illustrates monthly measurements of the wet deposition of copper ions (Cu²⁺) and zinc ions (Zn²⁺) in precipitation over a calendar year. Experimental Setup and Data Collection: Researchers collected precipitation samples from a specific location on a monthly basis. Each sample was analyzed to determine the concentration of copper and zinc ions deposited from the atmosphere, using analytical techniques such as atomic absorption spectroscopy or inductively coupled plasma mass spectrometry (ICP-MS). The concentrations, expressed in micrograms per square meter (µg/m²), indicate the amount of each metal ion deposited on the surface over a given month. Findings: The top graph shows the monthly wet deposition of Cu²⁺, which generally fluctuates between 50 and 100 µg/m², with higher levels in April and September. The bottom graph depicts the deposition of Zn²⁺, which has a higher range, peaking around January and then dropping mid-year, with another minor peak in December. These seasonal variations may be due to differences in industrial activity, weather patterns, or other environmental factors affecting metal distribution throughout the year.

What was the likely purpose of measuring the monthly wet deposition of copper and zinc ions in this experiment?

In which month was the highest concentration of Zn2+ deposited according to the figure?

If another metal, such as lead (Pb2+), were to be added to the study, what would be the most useful next step to determine its seasonal deposition pattern?

Researchers measured the amount of oxygen consumed by fish in different temperatures of water. If a fish in 20°C water consumed 2 mg/L of oxygen, how much oxygen would it likely consume in 25°C water, assuming the trend is that oxygen consumption increases with temperature?

A botanist recorded the height of a plant species under different amounts of daily sunlight. According to her data, the height of the plants was directly proportional to the hours of sunlight per day. Which of the following statements correctly describes this relationship?

An experiment was conducted to study the effect of soil pH on plant growth. Three types of soil with pH levels of 5.0, 6.5, and 8.0 were used. Plants in soil with a pH of 6.5 grew best. Based on this information, which of the following pH levels would likely lead to the poorest plant growth?

A study compared the reaction times of people when exposed to three different sounds: high-pitched, low-pitched, and white noise. Each participant was exposed to all three sounds in random order, and their reaction times were recorded. To ensure fair comparisons, each participant was given a break between sounds. Which of the following aspects of the study design most directly helps control for the effects of fatigue on reaction time?

Two scientists offer different explanations for the increase in global temperatures. Scientist 1 claims that the increase is due primarily to natural climate cycles that Earth has experienced over millions of years. Scientist 2 argues that human activities, such as burning fossil fuels and deforestation, are the main causes of the temperature rise. Which of the following observations would most likely support Scientist 2’s argument?

Two biologists have different hypotheses regarding why a specific type of bird migrates earlier each year. Biologist A believes that the birds are responding to genetic changes that favor early migration. Biologist B believes that the birds are responding to changes in climate, such as warmer temperatures arriving earlier in the year. Which of the following findings would weaken Biologist A’s hypothesis?