Why Is It That All Neurons in a Healthy Adult

Multiple Choice

Why is it that all neurons in a healthy adult brain have made appropriate connections?

A) Chemical messages from our muscles tell our brain how many neurons to form and that number perfectly matches the connections required.
B) If an axon does not make the appropriate connections by a certain age, it dies.
C) We are born with all connections formed.
D) Connections form rapidly, but we learn to use whatever connections have formed.