What structure provides support and protection for plant cells?

The cell wall is the correct answer because it serves a crucial role in providing both support and protection to plant cells. Composed primarily of cellulose, which is a carbohydrate, the cell wall offers structural integrity to plants, allowing them to maintain their shape and rigidity. This is essential for plants, as they do not have a skeleton to provide physical support.

Additionally, the cell wall acts as a protective barrier, safeguarding the internal components of the cell from external stresses, such as mechanical injury or pathogen invasion. It also helps regulate water uptake in the cells, which is particularly important for maintaining turgor pressure, a factor that keeps plants upright and healthy.

In contrast, while the cell membrane plays a role in protecting the cell and controlling what enters and exits, it lacks the rigidity and support provided by the cell wall. Cytoplasm refers to the jelly-like substance within the cell, where various organelles are suspended, and it does not function to protect or provide structural support. The nucleus, which houses genetic material, is pivotal for cellular control and function but is not involved in providing structural support or protection to the cell itself.