Which of the following is not part of the cell theory?

A. Every living thing is composed of cells.

B. Cells come from pre-existing cells.

C. Cells are the basic unit and structure of all living things.

D. Every cell has a nucleus that contains genetic material.

The option D) 'Every cell has a nucleus that contains genetic material' is not a part of the cell theory.

Explanation:

The cell theory has three main postulates which are:

All living things are made up of a cell or different cells. All cells arise from pre-existing cells Cells are the basic unit of life.

The cell theory does not claim that every cell shall have a nucleus. The prokaryotes lack a nucleus yet still are living things. However, all cells will have genetic material in the form of DNA or RNA.