Fossil fuels are burned to produce energy, they

a. produce air pollutants that can affect the quality of air

b. release excess carbon dioxide that increases the rate of photosynthesis

c. form heavy fall from heat collecting over the ocean

d. form radioactive particles in the atmosphere

(d) rivers.

explanation:

civilizations developed around rivers because their waters provided places to hunt and fish. also, as the rivers flooded, the lands around them became fertile. this allowed them to support farming. this is especially true of the nile river, which flooded the same time each year.

the viking voyages took place during the middle ages, which was about this time. 500 to 1350. the viking voyages took place during the middle ages, which was about this time.

i can't answer answer this if i dont have the things to check that apply