Urban heat islands can cause an increase in pollution, which is very harmful to people’s health.
a. heat
b. ozone
c. runoff
d. water

What we know about this question is that those are urban heat islands: urban places with higher temperatures than the places around those as a result of the existing infrastructure and high use of energy by humans. They create heat pollution - so the correct answer is a)

Answer they are produced by collision of tectonic plates;