Answer:
7-8 million years
Explanation:
There is many scientific evidences present from which scientists concluded that the humans evolved from chimpanzees about 7-8 million years and the ability to walk on two legs evolved about 4 millions year ago. There are a variety of physical and behavior changes occurred in the human while evolving from apes or chimpanzees. It takes millions of years to change occurs in the DNA of an organism.
