Which of the following causes rocks to break down into smaller pieces? A. Weather
B. water
C. time
D. all of the above

All of the above
rocks break down as time goes by, especially since it’s growing older
water + weather also breaks down rocks into smaller pieces

I would say D in a perfect situation, but time in of itself doesn’t really have so much of a say without all of the other variables. But the best one is D.

Decomposition is the cycle at which bacteria breaks down any organic material into the soil