Explain how failing to conserve water can lead to an increase in water contamination.

Crop irrigation is one way in which freshwater resources are consumed. Failure to conserve water during irrigation can lead to an increase in pollution that results from runoff. Natural filters are diminished by the overuse of water resources, which leads to an increase in water contamination that would have been filtered by these natural sources. With the increased demands placed upon sewage systems comes an increased likelihood of sewage system failures, which is another potential increase in water contamination.

Explanation:

This is the "possible answer" E2020 gives you at the end of the test.

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.