Your skeleton is made of more than 200 bones. It has three main jobs: it supports your body so you can stand up, it protects soft organs, and it helps you move. Your skull protects your brain, and your ribs protect your heart and lungs.
Bones cannot move by themselves. Muscles are joined to bones and pull on them. Muscles work in pairs: when your biceps contracts it pulls your lower arm up, and when your triceps contracts it pulls it back down. Bones meet at joints, such as the knee and elbow. Animals with a skeleton inside are vertebrates; insects have a hard case on the outside called an exoskeleton.
Worked example
Which bone protects the brain?
- The brain is soft and inside the head.
- The bone that surrounds it is the skull.
Answer:So the skull protects the brain.
Key words
- skeleton
- all the bones of the body
- muscle
- pulls on bones to make them move
- joint
- where two bones meet
- contract
- get shorter and pull
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New questions every time.
NGSS-referenced: 4-LS1-1