A hard structure that is inside some animal's bodies, provides support, and makes up the skeleton.

• joint

• backbone

• bone

• ball and socket

Two or more bones that come together...

• skeleton

• joint

• backbone

• supports

The elbow and knee are this kind of joint

• hinge

• ball and socket

• backbone

• support

Shoulders and hips are this kind of joint

• backbone

• hinge

• skeleton

• ball and socket

Part of the skeleton that is strong and flexible material

• bone

• joints

• cartilage

• muscles

A structure that contracts and relaxes to produce movement.

• muscle

• bone

• cartilage

• joint

Bones inside a bird's body are hollow.

• True

• False

A lightweight, flat structure that forms the outside covering of a bird's body.

• wing

• muscle

• scale

• feather

A flattened structure on the outside of a fish that helps it move, steer, and balance.

• fin

• scale

• muscle

Fish are covered with hard, slippery plates called:

• fins

• scales

• sails

• muscles