How does the author elaborate on the events that happened between 1955 and 1970?

The author provides facts about a and their effects. Research led the government to that cause air pollution. In response, many businesses were forced to

you need to make an explanation. so, since you did not include one, so no one, and i mean no one can unfortunately you,

the development of trade during the middle age increased to the change given in the agriculture, which gave money, industry and markets a bigger importance in economy. the agriculture production was more than the consumption, which meant the creation of wider markets out of the areas. besides, with the end of multiple wars, the population increased and new trade routes were created.

the answer is b. the tracer looks harmless in flight, but the pilot’s bitten lips and white knuckles suggest how dangerous it can be.