Final answer:
The Himalayan rivers, such as the Indus, Ganges, and Brahmaputra, flow across South Asia in different directions; the Indus flows into the Arabian Sea while the Ganges and Brahmaputra eventually merge and reach the Bay of Bengal.
Step-by-step explanation:
The rivers originating in the Himalayas flow in various directions across South Asia, extending their reach and providing crucial water resources for several countries. Specifically, the Indus River originates in the Tibetan Plateau near Lake Mansarovar and flows to the northwest through India into Pakistan and then to the south into the Arabian Sea. This river, alongside its four main tributaries, forms the 'land of the five rivers' or Punjab in Pakistan and India.
The Ganges River is another significant river that rises in the western Himalayas and flows southeast through the Gangetic Plain of India into Bangladesh, where it joins the Brahmaputra River before emptying into the Bay of Bengal. The Brahmaputra River starts in southwestern Tibet, winds through the Himalayas, enters northeastern India, merges with the Ganges, and eventually reaches the Bay of Bengal. Lastly, the Brahmaputra flows eastward initially but then takes a sharp turn towards the south, entering India in the state of Arunachal Pradesh, and continues its journey into Bangladesh.