shakil ansari, put search words "animal worship" in any internet serach engine and read the article to know how the system of worship originated. Hinduism is not a religion in its narrow sense. It is a conglomeration of various beliefs and even non-belief (atheism).
And of course caste system exists in Islam and Christianity. There are more than 12 castes in Islam in AP itself apart from two broad division called "Ajlaf" and "Ashraf". Again put serach words "Caste system in Islam" are see the result.
