Definition: Environment
is the natural surroundings or
conditions in which a plant,
organism, or animal is found.
Ecology is the study of species
in their environment.
How do cacti
survive in the
desert without water?
Find out on pages 62–63
Why do
zebras prefer
to live in herds?
Find out on pages
64–65Only 3 percent of the world’s water is fresh water. More than 65 percent of this is ice.
The volume of water in the Pacific Ocean is the same size as the Moon.
The biggest hot desert is the Sahara. It covers one-third of the area of Africa.
The Aral Sea has almost dried up because the rivers that supply it have been diverted.
Eighty percent of forests have been cut down by humans in the past 10,000 years.
AND ECOLOGYENVIRONMENT