a) ______science is te study of organisms in relation to surroundings.
b) Undesirable change in the physical, chemical or biological characteristics of air, land and water that affect human life adversely is called______.

Explanation

### Step-by-Step Text Solution:

a) The science that studies organisms in relation to their surroundings is known as **Environmental Science**. This field examines how living organisms interact with their environment, including the impact of human activities on ecosystems.

b) The term used to describe an undesirable change in the physical, chemical, or biological characteristics of air, land, and water that adversely affects human life is called **Pollution**. Pollution can manifest in various forms, such as air pollution, water pollution, and land pollution, and is caused by harmful substances known as pollutants.