Question

question 1
which process helps the brain become more efficient during the teenage years?
○ adding more brain cells rapidly
○ increasing brain size overall
○ producing more blood flow
○ removing unused neural connections
question 2
what is a key function of the protective coating around nerve fibers in the brain?
○ improving speed of communication between brain cells
○ creating new brain cells
○ controlling body temperature
○ storing memories more effectively

Explanation:

Question 1

During teenage years, the brain becomes more efficient through pruning, which is removing unused neural connections. Adding more brain cells rapidly (neurogenesis is not the main process here), increasing brain size overall, or producing more blood flow don't directly relate to efficiency improvement via pruning.

The protective coating around nerve fibers (myelin sheath) insulates them and speeds up the transmission of electrical signals (communication) between brain cells. It doesn't create new brain cells, control body temperature, or store memories.

Answer:

D. Removing unused neural connections

Question 2