The most common source of water contamination is
a. sewage
b. pesticides
c. fertilizers
d. none of the above

Option (a) is the correct answer.

Explanation:

Sewage water is the waste water from various sources like homes, industries, offices etc.  It includes lot of organic, inorganic and other impurities like human faceces, vegetable waste, fruit waste, nitrogen, phosphorous waste etc.

This sewage water passes through different areas and then finally mixes into the river and sea water causing contamination.

Thus, we can conclude that sewage is the most most common source of water contamination.

they are both synthetic elements

explanation:

d

in chemistry, adhesion and cohesion are attractive forces that exist between molecules. they hold the molecules together from each other. they are different in that adhesive force exists between molecules of different substance while cohesive force happens between molecules of same substance.

adhesion between water and glass causes water molecules at the edge of water and glass interface to climb up the wall in a narrow glass tube. this is called capillary action. cohesion is what gives glass its shape and causes water to form a droplet.