Question

Jami is doing an experiment to find out how temperature slows down or speeds up the sprouting of bean seeds. To prepare for the experiment, she plans to put soil into three foam cups and place six seeds in each cup. When Jami performs the experiment, which of the following should she keep the same for all of the cups of beans?
I. the amount of sunlight
II. the amount of water
III. the temperature
IV. the amount of fertilizer


A. I, II, and IV only
B. I and III only
C. I and II only
D. II and III only

Answer 1

Answer: A) I, II, and IV only
----
The things you want to keep the same are the controls. 
Keeping these things the same will help your independent variable, what you're changing (aka temperature), to be the only thing affecting your dependent variable, what you're measuring that usually changes because of the independent variable (aka speed of sprouting), giving you more accurate results.

From your list of choices, notice that the only thing you'll be changing is the III, the temperature. You want the amount of sunlight (I), water (II), and fertilizer (IV) to remain the same, or else those things might affect your final results. You want temperature to be the only thing affecting your final results!

Answer 2

the answer is A because When performing an experiment, it is important to change only one independent variable at a time.

In[?] this experiment, since Jami wants to see how different temperatures [?]affect sprouting, she must change the temperature, but she should leave the amount of sunlight, water, and fertilizer the same for all of the cups of beans.

If[?] Jami changes two variables—such as temperature and water—at the same [?]time and then finds that some of the beans sprouted faster than others, [?]she will not know which change caused the sprouting to speed up.