Hello!
Your answer is The physical environment may affect human activities, and human activities may affect the environment.
Humans are limited by the physical environment - the physical environment is our source of resources, land, everything. For example, would you rather build your home on a steep mountain, or on grassy plains?
Human activities may also affect the environment. When you look at us, you can see many problems we cause which affect the environment. This includes releasing greenhouse gases into the environment, deforestation, etc.
Hope this helps!