HELPPP!! What are the topic sentences, in this essay?

Learning a Musical Instrument
You sit down at the piano, open your music book, and begin to prac ce.
It is not easy, and you make a lot of mistakes. You wonder, “Is it worth
the eff ort to learn a musical instrument?” The answer is, “Yes!” Learning
to play a musical instrument can posi vely impact your brain and your
character.
Learning to play a musical instrument makes you smarter. Studies have
shown that playing an instrument improves your memory and helps you
do be er at other subjects such as math. These benefi ts alone make
prac cing an instrument worthwhile.
What's more, playing an instrument can do great things for your
character. As you are prac cing, you are learning important character
traits such as responsibility, discipline, confi dence, and perseverance.
Gaining these traits will posi vely aff ect many areas of your life.
Prac cing an instrument may not be easy. However, when it gets
hard, remember that you are doing more than just learning to play an
instrument—you’re also increasing your brain power and improving your
character.