In an experiment, researchers subjected frogs to various levels of the herbicide atrazine while keeping all other variables constant.This is an example of a _______ experiment.
A) controlled
B) repeated
C) laboratory
D) comparative
E) biased

Question

Quizplus · Accepted Answer

The experiment described is an example of a controlled experiment because the researchers kept all other variables constant except for the one they were testing (levels of the herbicide atrazine).

In an Experiment, Researchers Subjected Frogs to Various Levels of the Herbicide