AST Science Reasoning 1

Question 1

In a controlled experiment, the variable that the researcher deliberately changes is called the:

Accepted Answer

Independent variable

Answer

The independent variable is intentionally manipulated by the researcher to observe its effect on the dependent variable.

Question 2

A student notices that plants near a window grow faster than those in a dark corner. What is the most reasonable hypothesis?

Accepted Answer

Light exposure increases plant growth rate.

Answer

Since the observed difference relates to proximity to a light source, the most direct hypothesis involves light exposure.

Question 3

A graph shows that as temperature increases, enzyme activity first rises then falls sharply. What can be concluded?

Accepted Answer

Enzymes have an optimal temperature range beyond which they denature.

Answer

Enzymes function best within an optimal temperature range; excessive heat disrupts their structure (denaturation).

Question 4

Which of the following best describes a scientific theory?

Accepted Answer

A well-substantiated explanation supported by extensive evidence

Answer

A scientific theory is a rigorously tested explanation supported by a large body of evidence, not merely a guess.

Question 5

In an experiment, results that support the null hypothesis mean:

Accepted Answer

No significant effect was found between variables.

Answer

Supporting the null hypothesis means the data showed no statistically significant relationship between the variables tested.

AST - ACT Scaling Test Practice Test