Answer:
chemical reactions
Explanation:
Chemical reactions like weathering can cause rock and earth movement, plants grow from rain which is weathering, snow is weathering and cold winters is freezing water. I don't see how flowing water can contribute to weathering because in rivers, creeks, etc, always flowing. So if flowing water is always moving, it's not caused by weathering.
I EDITED MY ANSWER:
Physical weathering is caused by purely mechanical changes to the rock, while chemical weathering is caused by chemical reactions. The answer is chemical reactions
