Answer:
the answer is changes gradually
A control group of the experiment is the one in which no treatment or intervention is given. So, in your case, the pea plants in which was not subjected any of the fertilizers, will serve as a control group. This is a negative control. A positive control group is the one in which an established treatment is given, which definitely leads to the production of the desired character. So, in your case, a very good well-known fertilizer which has a positive control on the growth of the pea plant, would serve as a positive control.
The answer is true because you cant live without water
When referring to knowing where to find something when you need it you mean that you do not need a memorization of all things, you just need a source to find it when in need. I hope this answer suited your needs.