Question

1. an experiment that tests only one factor at a time by using a comparison of a control group and an experimental group is?

a) a theory
b) a dependent variable
c) a controlled experiment
d) an independent variable
d) it is an if/then statement

Explanation:

在实验中，实验组（experimental group）是接受实验处理（即改变一个因素）的组，而对照组（control group）不接受该处理。题目问“An experiment that tests only one factor at a time by using a comparison of a control group and an experimental group”（通过对比对照组和实验组来一次只测试一个因素的实验）是什么，这符合“受控实验（controlled experiment）”的定义。

Answer:

C. a controlled experiment