What can water do to the rock to weather it

The water can come from rain and this can be called chemical weathering or it can break apart rocks in a process of Frost wedging.

Explanation:

Frost wedging is considered mechanical weathering and it breaks rocks by freezing water in which expands the water by 9% every time it freezes expanding a crack or cracks in a rock more and more

b. regulated is the actual answer to your question.

explanation:

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%