1. Living things depend on ____ for survival.

1. ___ is everything that makes up the surroundings of a living thing.

___ is the contamination or dirtying of the environment by the discharge of harmful substances into the air, water, or soil.

The burning of fuels in houses, factories, and vehicles adds smoke and poisonous substances to the environment, causing ____.

Waste from our homes and factories are dumped into rivers, lakes, and seas, causing ____.

Wastes are also often thrown or buried, causing ____.