Question

what is the difference in the number of neurons in the human brain at age 2 compared to the number of neurons at birth? it is not possible to determine whether any change in the number of neurons has occurred. the number of neurons does not change between birth and age 2. there are 50% fewer neurons at age 2. there are 50% more neurons at age 2.

Explanation:

The human brain has a large - scale over - production of neurons early in development, followed by pruning. By age 2, there is significant pruning of neurons. So, there are 50% fewer neurons at age 2 compared to birth.

Answer:

There are 50% fewer neurons at age 2.