Octopuses are perhaps the most unusual creatures to have ever inhabited the ocean. Their soft body, eight arms, and high ...

Like most vertebrates, humans only have one heart, which is usually located near the front and middle of the chest, slightly to the left of the breastbone. The heart’s primary function is to pump ...

For humans and most vertebrates, life depends on a single heart pumping blood throughout the body. In this slideshow, we’ll ...