The Revised Ames Test,Bruce Ames Mixed Chemicals with Homogenized Rat

the revised Ames test,Bruce Ames mixed chemicals with homogenized rat liver prior to adding them to bacteria to assess their mutagenicity.What was the purpose of this step of the experiment?

A) To determine whether the chemicals killed mammalian cells
B) To determine whether the chemicals induced cancer in mammalian cells
C) To detoxify the chemicals prior to assessing their mutagenicity
D) To metabolically activate the chemicals prior to assessing their mutagenicity
E) None of the above