I believe the answer is two
The answer to your question is the third option "1.079 kg/m<span>3
</span>"
A: incorrect because there will be no effect on keeping the rats in separate cage in the same room at the time of the experiment.
C: incorrect because it's depend upon scientist whether he wants to record the observation on the graph or on the table. Thus, no affect will be caused on the observations.
D: incorrect because peer review is done only after the experiment is completed.
Thus, statement B is correct because the growth graph of male and female of any species is different. Male tend to grow more than their female counterparts. So, for the process of the study it is essential that all the rats included are either male or female.
Hence, option (B) is correct.
You are right!! Good job!!!