In a high school laboratory, which of the following constitutes an experiment?
I. learning to use a microscope by examining fixed specimens on slides
II. being able to examine swimming protists under a microscope
III. extracting pigments from plant leaves and separating the types of pigments for identification
IV. preparing root tips for examination by staining them
A) I only
B) II only
C) III only
D) II and III only
E) II, III, and IV
Answer: C