In an Experimental Procedure,the Researcher Has Established Multiple Levels of a Chemical,or

Multiple Choice

In an experimental procedure,the researcher has established multiple levels of a chemical,or amounts of light,or some other factor at the beginning of the experiment,in order to determine if and how much the biological system responds.The manipulated factor at varying levels is the

A) control group.
B) Both control group and standardized variable are correct.
C) dependent variable.
D) standardized variable.
E) independent variable.