Ancient India gave us buddisum.It's a religion.
hiduism
The Aryans brought with them Hinduism.
With their religion.
Yes, and it is so...
Karma and Samsara are concepts from the ancient Hindu religion, which is still practiced in modern India.
buddians
Most were Hindu
Yes it did. We had slaves in ancient India too.
Hinduism is the most practiced religion. It has been prevalent from the start.
Yes, it did. No ancient society ever existed that did not believe in the supernatural. For a few details, see: Religion in ancient India and the Indus
Hindoism