Final answer:
a) Erosion. Erosion is the process that involves the Earth's surface and is both a physical and chemical change.
Step-by-step explanation:
Based on the given information and references, the process that involves the Earth's surface and is both a physical and chemical change is erosion (option a).
Erosion is the process by which the Earth's surface is worn away by natural forces like wind, water, or ice. It involves the physical removal or displacement of soil, rocks, or other materials, thereby changing the Earth's surface.
While erosion is primarily a physical change, it can also involve chemical changes. For example, when water erodes rock formations, it can dissolve and transport minerals, creating chemical changes in the environment.