Why people shouldn't be sent to Mars?
A variation is a reference to the differences or deviations, such as the structure and form, as for crossing over is the exchange of genetic material between the non-sister chromatids of the homologous chromosomes during meiosis.
Answer:
protection
Explanation:
The cell wall is the protective, semi-permeable outer layer of a plant cell. A major function of the cell wall is to give the cell strength and structure, and to filter molecules that pass in and out of the cell.