What is meant by the term optimum temperature?

optimum pretty much means the best. So it just means "The best temperature"

the correct answer is b. possesses the characteristic of compartmentalization of organelles, wherein the organelles are bound by membranes.

explanation:

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.