Prokaryotic - cells that don’t contain a nucleus, for example bacteria cells
Eukaryotic - cells that contain a nucleus, for example plant and animal cells
Chemical A the other ones dont even exist
A Urea first thing that showed up when you look up the question
Answer:
Indicator species, organism—often a microorganism or a plant—that serves as a measure of the environmental conditions that exist in a given locale. ... For example, greasewood indicates saline soil; mosses often indicate acid soil. Tubifex worms indicate oxygen-poor and stagnant water unfit to drink.