Something that is hard to figure out or understand. People can try to find clues to solve a mystery.
Pieces of information that help you find the answer to a mystery. The soccer ball in this picture is a clue. It shows what broke the vase.
To look carefully at something. This child is examining a butterfly with a magnifying glass.
A warm-blooded animal. Female mammals feed milk to their babies. Whales and dolphins are mammals. So are dogs, cats, and people.
An animal without a backbone. Squid and jellyfish are invertebrates.