Living Environment Translated Arabic 2014 | Page 74

3. An ecosystem is made up of the living organisms (biotic factors)
and the nonliving parts ( abiotic factors) of an area.
4. Freshwater Ecosystems:
a. Temperature, light, salt, and dissolved oxygen are
important factors.
b. Rivers, streams, lakes, ponds, and wetlands are freshwater
ecosystems.
c. Human activities can pollute aquatic ( water) ecosystems.
5. Wetlands are areas that are covered with water most of the year.
They are found in a