Circulate your way through the heart, blood vessels, and blood. This trio delivers oxygen and nutrients to the body, controls body temperature and hormones, and defends against harmful invaders.
Jellyfish, sea anemones, and corals are members of the stinging cnidarian family. Flatworms, roundworms, and earthworms are three major types of worms.
We use textiles when we are awake and when we sleep. Some are made from the same natural fibers that people have used for thousands of years, while others are synthetic.
Journey to the hot, steamy layers of tropical rain forests around the world to learn about the climate, creatures, and plants of this endangered biome.