Why is indoor air pollution a serious health hazard in some developing countries?
a. the burning of coal releases significant amounts of particulates into the air.
b. people smoke more in developing countries.
c. many homes rely on indoor burning of wood or dung without proper ventilation.
d. most houses in these countries are well insulated, increasing household exposure to radiation?

Developing countries means that they are the country that are still in the progress of growing to be able to advance, which means that they are not as advanced as compared of the developed countries. The answer to the question above is letter c. It is because they are developing countries, most of them don't have proper ventilation, which make them rely on burning wood or dung. With this, it pollutes the air in their homes, leading to serious health hazards.

Ijust took the test on edgenuity and the answer is "life would cease to exist". hope this !