Answer: Based on what I learnt in biology I believe the correct answer is brain plasticity.
Explanation:
What is brain plasticity?
Brain plasticity refers to the ability of our brain to adjust to the changes brought to us by change in situations that we experience in life.
Jerry was previously exposed to an environment that one may refer to as inappropriate for raising a child , where his mom probably brought drugs to sell in their house and also might have done her work whilst Jeremy was there.
This might have affected his ability to cope with his school work because this probably affected him mentally.
When the situation change and now he was experiencing a different environment where there is love and comfort , his brain adjusted to this positive change which yielded positive results in his school work.