rain forests receive a lot of rain every year. They even have rain in the name. deserts are vey dry and hot so they don't receive a lot of rain. tundra's are cold and dry. They don't receive much rain either. Grass lands I am not really sure about but it said to pick three and the other two were rain forests so I think it is grass lands. sorry if I am wrong.
The stem relies on the pressure of the plant cells to maintain its rigidity. The plant cells shrink when they lose water, losing their rigidness in the process.
