(a) What depletes ozone in the stratosphere? How does this affect human life?
(b) Explain biomagnification of DDT in an aquatic food chain. How does it affect the bird population?

Explanation

### Step-by-Step Text Solution

**(a) What depletes ozone in the stratosphere? How does this affect human life?**

1. **Understanding Ozone Layer**: The ozone layer is located in the stratosphere and serves as a protective shield for the Earth. It absorbs the majority of the sun's harmful ultraviolet (UV) radiation.

2. **Ozone Depletion Agents**: The primary agents responsible for ozone depletion are chlorofluorocarbons (CFCs). These are man-made compounds commonly used in refrigeration, air conditioning, and aerosol propellants.

...