Mice Are Given a Protein Injection That Is Designed to Promote

Multiple Choice

Mice are given a protein injection that is designed to promote physical growth.Fifty mice are randomly selected for evaluation in the study.Some of the mice are injected with high levels of the protein, some are injected with low levels of the protein, and a third group receives a placebo (saline injection) .The mice's growth is recorded and compared.In this study, the variable is best described as:

A) 50 randomly selected mice.
B) all mice that receive a protein injection.
C) the type of protein used.
D) the amount of protein injected.