Answer:
The environment
Explanation:
The environment, as well as genetics, influence in children development. When a children grows up in an environment with many stimulus, it makes the child learn faster and adapt to this environment and develop in a faster way than their peers who don't grow up in such rich environment.
In the case of Peter, his parents are very academic and their house has many books and they are very intellectual people, therefore this can be a source of Peter's high intelligence.
