Question

which is a part of the cell theory?
cells come from pre - existing cells
cells have a nucleus
organisms with one cell must be seen with a microscope
organisms must have more than one cell to live

Explanation:

Cell theory has three main points: all living things are made of cells, cells are the basic unit of life, and cells come from pre - existing cells. The option "cells have a nucleus" is not part of the general cell theory (prokaryotic cells don't have a nucleus). The option "organisms with one cell must be seen with a microscope" is a practical observation but not a core part of the theory. The option "organisms must have more than one cell to live" is wrong as there are single - celled organisms.

Answer:

cells come from pre - existing cells