Pearson a(n) is a substance that appears to be identical to a drug being tested but has no known effect on the condition being studied.

h

explanation:

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.

not sure if this is what you'r looking for prokaryotes have organelles hope this out at least.