Answer and Explanation:
Hinduism absorbed many philosophies taken to India during the Aryan invasions. These invasions promoted a missigenation not only of the "races" of the peoples, but also of culture, religion and customs.
The Indian region, before the Aryan invasions, already had a polytheistic character and the presentation of gods as anthropomorphic animals. However, the Aryan invasion brought the concept of] castes to this religion. This is because the Aryans believed that the population should be divided by castes and these castes were related to each person's birthplace. For Aryans (and Hinduists) those born from the head of the most powerful god were the dominant social class; those who were born in the arms were the warriors, those who were born in the legs were the producers and those who were born in the feet were the servants.
Both Indian and Aryan culture were very influential at that time, which allowed the development and growth of Hinduism to be itemized and better spread by other territories.