Answer: Answer: Cell wall has the function of protecting and supporting cells;

Cell membrane protects the internal structure of cells and controls the entry and exit of substances inside and outside cells. It is selective to substances, allowing useful substances to enter cells and keeping other substances out of cells. At the same time, it can also discharge the waste generated in the battery to the outside of the battery.

Nuclear-plays an important role in biological inheritance. The nucleus contains genetic material;

There are many substances in the cytoplasm, and the cytoplasm of living cells has fluidity, which is beneficial to the exchange of substances between cells and the external environment.

According to the above, the main reason why plant cells keep a certain shape is the support of cell walls.