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 with low levels,and a third group receives a placebo (saline injection) .The amount of growth of the mice 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.