Question

An experiment in which only one variable is changed is a(an) __________ experiment.

A. randomized
B. natural
C. double blind
D. controlled

Answer 1

Hi

The correct answer is : D

Because a control experiment is one in which a hypothesis is tested by the manipulation of a single variable.

I hope that's help:)

Answer 2

D. controlled
is the right answer because an experiment in which an observer tests a hypothesis by looking for changes carried by alterations to a variable.