Scientists Want to Determine Whether Chemical X, a Component of Fertilizer

Multiple Choice

Scientists want to determine whether chemical X, a component of fertilizer, is harmful to fish.  They treat fish in the laboratory with increasing amounts of the chemical for one week and then measure their viability. Fish that are not treated with chemical X are considered ____. ​

A) the null hypothesis
B) experimental data
C) replicates
D) controls
E) experimental variables