If the aryans had not invaded the indus river valley, what might you predict?
a. other people would have conquered the regionb. the ancient indus valley cities would still exist todayc. hinduism would not have developedd. the indus people would not have had their own region

Around 2800 BC, a new civilization rose along the banks of the Indus river (just like other early civilizations, along a river) in India. The place in which it arose was largely ideal, and was well-protected by the natural boundaries of the Hindu Kush Mountains. Although this limited outside contact, it is known that the early Indians used the Khyber pass through this range to communicate with other civilizations. In the future, groups would use this same pass to invade India.

Very useful. it is to learn because history repeats itself so learning about it those mistakes not happen again.