The wording and language of these options are a little unclear but- The answer is D.
A) is incorrect because the independent variable is independent so it isn’t effected by anything in or experiment. Because o this The independent variable is the thing we *change* in order to see what happens to everything else (dependent). Keyword = change
A control is a thing we keep the same. So A cannot be correct because our independent variable is not a control. It’s the opposite of a control because an independent is always being changed.
B) is incorrect because the dependent variable should change if there’s a relationship between the two things we are studying.
C) is incorrect because there is no relationship between cows and the concept of an independent variable
D) Is correct because we are testing (playing around with) the independent variable. And when we do that, we see a change in the dependent. So the dependent is a result of change.
