It would slow down in the stage of growing or
Answer:
The answer is C
Explanation:
That is the only one they have in common.
Answer:
I think she should try the experiment one set with fertilizer, and one without. The negative control group would be the set of rose bushes grown without the fertilizer, but under the exact same conditions as the experimental group. Then, if a difference is seen you can be sure it's accurate, since you tested with and without fertilizer under the same conditions. Sorry if i am wrong, I am not completly sure about this one. Again I might be wrong so sorry in advance.
The answer is DNA.
P.S If you need me to explain more I can just ask! :)
I hope this helps!