Question

Ten plants are grown in equal amounts of sunlight with equal amounts of water and varying amounts of fertilizer. Sunlight, water, and fertilizer are
a) experiments b) systems c) variables d) controls

D

Answer 1

fertilizer is variable. It says that.
the others are controls

Answer 2

It's asking what sunlight, water and fertilizer are

Answer 3

I told you

Answer 4

I agree with Damon; however, since neither c nor d can be correct, I think the answer must be b. The three together make a system.