Help please anyone

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.

How many cells are our body made of ? ♡

Despite the differences in mature plant cells, all of them are derived from meristem cells. the three major types of tissue systems develop from the meristem. meristems develop cells in all but which tissue?