The Nile and the Amazon are the two longest rivers in the world.

Dinosaurs lived on Earth for more than 160 million years.

Potatoes were the first vegetable grown in space.

Your body has about 600 muscles.

Earth's crust is broken into giant pieces called tectonic plates that move very slowly.

Some frogs can freeze solid in winter and thaw out alive in spring.

Pumpkins are a kind of fruit, because they grow from a flower and hold seeds.