9781422278611

CHAPTER 2 brains

1 + 2 = tree

Koalas have teensy-weensy brains. Their brains weigh 0.6 ounces (17 grams), which is about the size of a cherry tomato. Don’t ask them to do long division!

The more brain cells an animal has, the more complex its brain. Humans have around 100,000,000,000 brain cells! In comparison, a tiny cockroach has around 1,000,000 brain cells, while a fruit fly has only 250,000. That’s something we should cell-ebrate!

HAve you done your homework?

Your brain isn’t just for homework. No matter what your teacher says, you’re using your brain all the time—when you smell, when you breathe, when you run … even when you sleep! Like all animals, we use our brains without even knowing it!

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