Question

A group of biology students tests the growth of bacteria under different conditions. The students apply the same amount of bacteria to identical Petri dishes enriched with nutrients, then place each plate at a different temperature. The bacteria are allowed to grow for three days, after which the number of bacterial colonies on each plate is counted. What is the dependent variable in this experiment?

A.

the time of day that the experiment is performed

B.

the number of bacterial colonies after three days

C.

the temperature at which the colonies grew

D.

the nutrient type present in the Petri dishes
Which question is testable?








A.

How does changing the amount of water affect the growth of corn?

B.

Is it ethical to use human tissue removed during surgery for scientific research?

C.

Are you happy with your new job?

D.

Will people be disappointed if car insurance rates increase?

Answer 1

B. (The first one)

Step-by-step explanation:

the only thing that is different from the two perish dishes are the temp. this is the independent variable. the dependent variable is the result. in this case, the amount of bacteria after three days