How does the cell wall protect a plant cell?

The cell wall protects a plant cell by giving it protection and support.
The cell wall is made of cellulose which is a specialized sugar that helps give the wall structure and support to protect the inner part of the cell.

Well just think of it as a human body. without the skin, everything inside will be exposed and liquids and organs and all will likely fall out. same kinda goes for a plant cell wall. the wall protects everything from the outside and keeps everything inside of the plant. i truly hope this answer has helped.

Resistance than a bicycle? i'm not entirely sure

Yes yes yes very good