How do all multicellular organisms begin?

a.
as complex organisms

b.
as a single cell

c.
by expanding the size of their cells

d.
by creating all their cells at one time

A multicellular organism can also be referred as eukaryote different from a prokaryote which is an organism that has only one cell. In this problem, the multicellular organism begins by D. by creating all their cells at one time which exponentially increases the number of cells eventually.