📚 Part 1: Understanding Muscle and Bone Movement

1. What happens when a muscle contracts?

It gets longer and thinner

It gets shorter and thicker

It stays the same size

It disappears completely

2. Which of these connect muscles to bones?

Ligaments

Tendons

Cartilage

Blood vessels

3. What are antagonistic muscles?

Muscles that work against each other

Muscles that are the same size

Muscles that never work

Muscles that only work at night

4. Fill in the blanks: When your biceps muscle __________, your arm bends. When your triceps muscle __________, your arm straightens.

🔬 Part 2: Antagonistic Muscle Pairs

5. Complete the table showing what happens to antagonistic muscle pairs:

Action	Biceps	Triceps
Bending arm at elbow	_____________	_____________
Straightening arm at elbow	_____________	_____________

6. Explain why muscles work in pairs. Use the words contract, relax, and pull in your answer.

7. What would happen if your biceps muscle contracted but your triceps muscle didn't relax?

8. Name two other parts of your body that use antagonistic muscle pairs and describe one movement each makes:

9. Draw and label a simple diagram showing how the biceps and triceps work together to move the arm. Include: bone, muscle, tendon.

10. Reflection: How did making the model help you understand how muscles and bones work together?