The end of the stone age (around 10,000-12,000 years ago) witnessed the change from hunter-gatherer societies to agricultural societies. this led to the rise of civilization. one of the societal changes that occurred at this time was that people a. migrated south ahead of advancing glaciers. b. relied more on meat than plants for their diets. c. began to farm and live in permanent settlements. d. began to interact and trade with distant societies.

two jet streams that directly affect the formation of weather in the continental part are a polar jet and a subtropical jet. they are responsible for the transportation of weather systems, which directly affect people. the polar front is the boundary between cold air from the north pole and warmer equatorial air. both the polar jet and the subtropical jet blow from the west to the east, and follow the boundary between cold and warm air.

the strongest jet streams are polar jets, while subtropical jets are somewhat weaker.

the right answer is c. the polar jet stream is generaly stronger than the subtropical jet stream.

where is the passage