Answer:
1. Option C, There is a difference in air pressure
2. Over High altitude
Step-by-step explanation:
1. The air pressure for cold air is higher than that of warm air. It is so because the cold air is denser than that of warm air and thus has higher number of air molecules with in a given area . The cold air being denser sinks while the warm air being lighter rises. Also the wind moves from cold areas towards the warm area.
Hence option C is correct
2. Jet streams are caused in regions which have high variations of difference between the temperature at different point of time. At high altitudes in polar region, the temperature during days is high while the temperature during night is extremely low and hence polar jet streams are caused
Thus, option A is correct