Final answer:
The monsoon is a seasonal reversal of winds that brings heavy rains to South Asia. In the summer, warm moist air is pulled in from the Bay of Bengal and Indian Ocean, resulting in rain. In the winter, cool, dry winds come from the north.
Step-by-step explanation:
The monsoon is a seasonal reversal of winds that brings heavy rains to South Asia. In the summer, the continent heats up, creating a vacuum that pulls in warm moist air from the Bay of Bengal and Indian Ocean. This moisture is then precipitated as rain, feeding the rivers and streams of the region.
In the winter, the cold, dry air above the Asian continent blows to the south, resulting in the winter monsoon. This season is characterized by cool, dry winds coming from the north. However, some parts of South Asia, such as Sri Lanka and southeastern India, experience a rainy winter monsoon due to the winds picking up moisture from the Bay of Bengal before reaching their shores.
Overall, the monsoon is a major source of support for South Asia's large population as it provides the water needed for agricultural production and replenishes the rivers and basins.