I think the answer is D. I’m bot sure though I learned about this last year so my memory on it isn’t the best
N an experiment the "control" is the group of people or object this is used to measure the effect of the variable. The "control" is the thing that does not change and is not the thing in question.
In an experiment the "variable" is the thing which is changed and manipulated by the experimenter. It is the effect of something,
Example: You want to test a drug. you get a group of 40 people. 20 people are given the pill, 20 people are not given the pill but a sugar pill. the people who have the pill is the "variable" and the people who dont have the pill is the "control".
300 BC by Greek philosophers
B. The water is likely contaminated with high levels of pollution or waste
