ACT Science Question and Answers 3

Question 1

Experiment 1 tested four fertilizer types on corn yield. Fertilizer C produced the highest average yield at 8.4 tons/acre, while no-fertilizer control produced 4.1 tons/acre. What is the percent increase for Fertilizer C over the control?

Accepted Answer

About 105%

Answer

Percent increase = (8.4 − 4.1)/4.1 × 100 = 4.3/4.1 × 100 ≈ 104.9%, approximately 105%.

Question 2

In a conflicting viewpoints passage, Student 1 argues that the universe is static and infinite, while Student 2 argues it is expanding from the Big Bang. The observed redshift of distant galaxies (light shifted toward longer wavelengths) best supports:

Accepted Answer

Student 2, because redshift indicates galaxies are moving away

Answer

Redshift of distant galaxies indicates they are receding from us — consistent with an expanding universe, which supports Student 2's Big Bang hypothesis.

Question 3

A scientist studies how temperature affects cricket chirp rate. The data shows a linear increase in chirps per minute from 60°F to 90°F. At 60°F, the rate is 80 chirps/min; at 90°F, it is 200 chirps/min. What is the approximate chirp rate at 75°F?

Accepted Answer

140 chirps/min

Answer

75°F is halfway between 60°F and 90°F. Halfway between 80 and 200 is (80 + 200)/2 = 140 chirps/min.

Question 4

A study compares two antibiotics against Bacteria X. Antibiotic A creates a 25 mm zone of inhibition; Antibiotic B creates a 10 mm zone. What does this indicate?

Accepted Answer

Antibiotic A is more effective against Bacteria X

Answer

A larger zone of inhibition indicates greater effectiveness. Antibiotic A's 25 mm zone vs. Antibiotic B's 10 mm zone shows Antibiotic A is more effective against Bacteria X.

Question 5

Which of the following experimental designs best controls for the placebo effect in a drug trial?

Accepted Answer

A double-blind placebo-controlled study

Answer

In a double-blind study, neither participants nor researchers know who receives the drug or placebo, eliminating bias from the placebo effect and researcher expectations.

ACT Practice Test

ACT Practice Test

ACT Science Question and Answers 3