Concept:Physical weathering breaks rocks without altering their mineral composition, while chemical weathering changes the minerals themselves.
Explanation:In physical weathering, rock is only broken into smaller pieces.
Its mineral composition remains unchanged.
In chemical weathering, reactions such as oxidation, hydration, and carbonation change the original minerals into new substances.
Therefore, the key difference is that chemical weathering changes the mineral composition of rock.
Answer:B. the mineral composition of rock is changed in chemical weathering.