Answer:
1. Monsoons are caused by temperature differences in the air over land and sea. They blow from colder to warmer areas. In a monsoon region in summer the land and the air above it become very hot. The nearby sea and the air above it are cooler.
2. Thunderstorms form when warm, moist air rises into cold air. The warm air becomes cooler, which causes moisture, called water vapor, to form small water droplets - a process called condensation. The cooled air drops lower in the atmosphere, warms and rises again.
3. ITCZ (Intertropical Convergence Zone) is caused by the convergence of northeast and southeast trade winds in the area encircling Earth near the Equator.
4. The main energy source of a tropical cyclone is water vapor which is abundant in the oceans and seas. When the sun heats up the earth surface, water vapor evaporates into the atmosphere and condenses into water droplets, a great amount of heat energy, which is locked up in the water vapor, is released.
