The reason why young brains are more plastic and more sensitive to stimulation to the outside world is as a result of availability of less myelin.
Myelin can be regarded as an insulating layer, that is found around nerves
Especially those in the brain as well as spinal cord. It helps in transmitting of quickly as well as efficiently along the nerve cells.
Learn more about Myelin at:
https://brainly.com/question/690266