1Today our teacher talked about how the human body works.
2Your heart is a muscle that pumps blood around your body.
3It beats about one hundred thousand times every single day.
4Blood carries oxygen from your lungs to every part of you.
5When you breathe in, your lungs fill up with air.
6Your body takes the oxygen and removes the carbon dioxide.
7Bones give your body its shape and protect your organs.
8A grown-up has just over two hundred bones in total.
9Muscles are attached to bones and help you move around.
10You use more than thirty muscles just to smile.
11Your stomach breaks food down into tiny useful pieces.
12The small intestine takes nutrients out of your food.
13Your brain sends messages through nerves at great speed.
14Skin is the largest organ and keeps germs outside.
15When you get cold, your body starts to shiver for warmth.
16Sweating helps your body cool down on hot days.
17Sleep gives your brain time to rest and repair itself.
18Drinking enough water keeps every system working well.
19Exercise makes your heart and muscles stronger over time.
20The class asked so many questions that the lesson ran late.