Final answer:
Animals burrowing in the ground is an example of biological weathering, which is the breakdown of rocks by living organisms.
Step-by-step explanation:
An example of biological weathering is animals burrowing in the ground. Biological weathering refers to the breakdown of rocks by living organisms, such as plants and animals. For instance, as animals burrow, they can move rocks and soil, which can lead to the breaking apart of rock materials. In contrast, the other options listed are examples of chemical and physical weathering processes. Feldspar reacting with water to form clay is chemical weathering, water freezing and expanding cracks in a rock is physical weathering, and acidic water dissolving soluble rocks and minerals is also chemical weathering.
Biological weathering is the process by which living organisms, such as animals, plants, and microorganisms, contribute to the breakdown and disintegration of rocks and minerals. Of the options provided, animals burrowing in the ground is the best example of biological weathering. Animals like earthworms, ants, and rodents create tunnels and burrows in the ground, which can break apart rocks and accelerate the process of weathering.