Choose the topic sentence that best fits the paragraph below. Scientists studied people who learned the new skill of
juggling. The juggling practice did help the brain grow
larger, but it shrank back to normal once the person
finished practicing the new skill. It seems that the brain
both grows and shrinks with the learning of a new skill.
A. Learning too many skills may cause the brain to grow to a larger
size than what is considered healthy by doctors.
B. Juggling is a difficult skill to learn for people of all ages.
C. There are many ways to grow the brain, but only some of these
methods cause permanent growth.
D. Studies show that even though the brain grows during a learning
process, it shrinks back to normal once the process is over.