Environment consists of both living and non-living things. Living things such as animals, plants, etc. interacts with both other living and non-living things. Similarly, non-living things such as soil, water, climate, temperature, sunlight, air, etc. interacts with other non-living and living things.
There is a close relationship between living organisms and environment. Ecology is the branch of science that studies the interaction between organisms and their environment.
The interaction of living beings, including human-beings, brings changes in the environment. Similarly, livings beings also display changes within them with the change in the environment.