In large cities around the world, people can usually see a ......... in the sky because of pollution. This is an environmental state that is formed from smog and the sun's rays that bounce off of the ground. It looks like a mist in the sky.

Some scientists and doctors are blaming toxic pollutants for birth......... found in young children and newborns. These are unhealthy and abnormal conditions that are caused by exposure to high levels of pollution.

......... is the process of cutting down trees in order to obtain and sell lumber in a financial market.

A water......... is a strainer-like object that removes impurities and pollutants from water sources. Some people attach these devices to their water faucets at home.

Some scientists are wholly devoted to the study of marine life and ocean environments. This area of study is called ......... .

Power......... are factories that produce and harness energy and release harmful emissions into the air.

The production of......... products is controversial in the environmental world because these are synthetic-based materials, such as PVC pipes, that cause a lot of harmful and toxic fumes.

Carbon......... is a natural gas found in our atmosphere. Humans breathe in oxygen and breath out this gas that plants, in turn, absorb and use to stay live. However, levels of this gas have increased in recent years because it is released when we burn coal, gasoline and oil. It is now considered a greenhouse gas.

Governments in some countries have agreed upon a carbon ......... . This is a fee that is based on how much carbon each country releases into the atmosphere each year.

An......... is a scientist who studies the natural relationship between living things and the environment.