A harmful material that can enter the biosphere through the land, air or water.

When nitrates and sulfates are released into the atmosphere, they combine with water vapor to form droplets of nitric acid and sulfuric acid. These droplets fall back to land as ______________________.

A naturally occurring gas that is vital to life on Earth. It screens out most of the ultraviolet radiation from the sun.

The destruction of the ozone layer by releasing harmful chemicals into the atmosphere is called ________________________.

The most important of the harmful, ozone -destroying chemicals is known as

Which term is used to describe the increase in the average temperature of the biosphere?

An increase in levels of which gas causes global warming?

Which chemical acts as a catalyst and speeds up the breakdown of ozone molecules in the upper atmosphere?

True or False? Acid rain can kill plants, damage soil, and poison aquatic ecosystems.

Where does smog come from?

CFC's are used...

Which of these is harmful to the environment?

The supply of fresh water on Earth is _______________________.