What is an example of a physical weathering? A: a metal tool left outside beginning to rust
B: microscopic organisms producing compounds that break down rock
C: a rock wearing down due to acid rain
D: bits being blown off a rock by heavy winds

D) Bits being blown off a rock by heavy winds

Explanation:

All the other answer choices are examples of chemical weathering.

Rusting is chemical weathering.

Compounds that break down rocks is chemical weathering.

Acid rain is chemical weathering.

Wind breaking rocks, however, is physical weathering.

the answer is d.) homologous; have mammary glands