Which one is not limiting factor for enzyme in photosynthesis

The following image is of a diatom. it lives in water and gets food from photosynthesis. it is encased in a hard shell made of something similar to glass or sand . a diatom is a(n) because it has a) multi-celled organism; specialized parts. b) vertebrate; a skeleton. c) insect; an exoskeleton. d) single-called organism; only one cell.

The organelle pictured is found in cells of and is theorized to have once been an independent organism.

Is genetic diversity the same as genetic variation?