The part of the cell that provides external protection and support for plants is the cell wall.

Here's why:

* Structure: The cell wall is a rigid, outermost layer that surrounds the cell membrane.

* Protection: It acts as a barrier, protecting the cell from damage and providing structural integrity.

* Support: The cell wall gives the plant its shape and allows it to stand upright against gravity.

* Composition: It's primarily composed of cellulose, a strong and flexible carbohydrate.

Let me know if you have any other questions!