Question

select the part whose main job is to give strength and stiffness to the cell. cell wall smooth endoplasmic reticulum chromosomes nucleus

Explanation:

To determine the cell part that provides strength and stiffness, we analyze each option:

• Cell wall: In plant cells (and some prokaryotes/fungi), the cell wall is a rigid structure made of cellulose (or other polymers) that gives the cell its shape, strength, and resistance to mechanical stress. It acts as an external support framework.
• Smooth endoplasmic reticulum (SER): Primarily involved in lipid synthesis, detoxification, and calcium storage. It has no role in providing structural strength to the cell.
• Chromosomes: These are structures within the nucleus that carry genetic information (DNA). Their function is related to heredity and cell division, not structural support.
• Nucleus: The control center of the cell, containing genetic material. It regulates cell activities but does not provide strength or stiffness.

Among these, the cell wall is the only structure responsible for imparting strength and stiffness to the cell.

Answer:

A. cell wall