Question

european cities contribute to water pollution when drains overflow and ______ spill(s) into rivers.
a. insects
b. water
c. vegetation
d. sewage
please select the best answer from the choices provided
○ a
○ b
○ c
○ d

Explanation:

The question relates to water pollution sources from urban drains. Sewage (wastewater from homes/businesses) is carried by drains; overflow leads to sewage spilling into rivers, causing pollution. Other options (insects, water, vegetation) do not cause pollution in this context.

Answer:

D. sewage