1. An origin is a fixed attatchment and a insertion moves with contraction.

2. An antagoinust is a muscle that opposes the action of another muscle.

3. An injury to one of the antagonist muscle pair could make movement in that area impossible, for the muscle wouldn't be able to return to it's position.

4. A tearing of a tendon could make it difficult to move that muscle, and it can be repaires by taking a pience of another tendon and replacing it with that.

5.A bird would not be able to fly if there was damage to the nerve in the wing, for the brain would not be able to send signals to the nerves in the wing to tell it to move/fly.