Usually, stranger wariness is first noticeable at months

Stranger wariness is obvious when an infant no longer smiles at any friendly face & cries if an unaccustomed person moves too close, too quickly. Stranger wariness appears fleetingly around 6 months of age, though it is not always detected and at full force by 10 to 14 months.

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.