The joints in a sea lion’s fl ippers help it turn and twist its body while swimming.


Putting Bones to Work Some joints move in a circle. Try rolling your shoulders. You use these kinds of joints to throw a ball. A sea lion uses the same kind of


joint to dive and swim. It uses these joints to move its flippers to turn its body. It can twist through seaweed while hunting for fish. Bones help you, sea lions, and other


vertebrates get around. Bones give bodies strength and support. Bones also protect bodies from damage. Just imagine what your life would be like without bones.


Wordwise


bone: one of the many pieces that make up a skeleton


joint: any part of a skeleton where two or more bones meet


muscle: a type of body tissue that can be tightened and relaxed to cause movement


skeleton: a strong framework that supports the body


vertebrate: an animal with a backbone


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