Answer:
Part (a):
Wind is caused by the difference in Atmospheric Pressure. Air moves from the area of Higher pressure to the area of Lower pressure whenever there is a change in Atmospheric pressure, this causes winds of different speeds. Moreover, Coriolis effect also causes winds due to Earth's rotation.
Part (b):
Wind direction can be determined by watching clouds in such a way that when we see the cloud movement from northeast to southwest direction, this means that wind at that position is blowing northeasterly with high pressure on left side and low pressure on right side.
Moreover, pressure of winds can be known by the instrument called Barometer that is placed at different places for calculation of wind pressure.
I hope t will help you!