Answer:
D. ceteris paribus
Step-by-step explanation:
Ceteris paribus is Latin for - all things being equal or constant.
In evaluating the effect of a factor in research it is important to keep all other factors constant so that the effect of the action of interest can isolated.
In the given scenario Dr. Ogechi is interested in studying the effects of aquarium temperature on the number of offspring produced by a certain species of fish.
For the effect of temperature to be accurately studied there is need for all other factors like pressure, salt content of water, oxygen content, and so on be constant.
This isolates effect of temperature on the experiment.