Science 8 · Unit 7: Diet and growth · Cambridge Lower Secondary Science Stage 8

Questions

1. 1. Why do muscles work in antagonistic pairs?

   • Bones move themselves.
   • Muscles can only pull, so one bends a joint and the other straightens it.
   • One muscle is always resting.
   • Muscles can only push.
   Check

2. 2. What type of joint is the knee?

   • a hinge joint
   • a ball-and-socket joint
   • a sliding joint
   • a fixed joint
   Check

3. 3. Which is a ball-and-socket joint?

   • the hip
   • the elbow
   • the knee
   • the knuckle
   Check

4. 4. Which muscle contracts to bend the elbow?

   • the biceps
   • the triceps
   • the calf
   • the diaphragm
   Check

5. 5. Which muscle contracts to straighten the elbow?

   • the heart
   • the biceps
   • the hamstring
   • the triceps
   Check

6. 6. When the biceps contracts, what does the triceps do?

   • contracts too
   • pushes
   • breaks
   • relaxes
   Check

7. 7. What is the long bone in the thigh called?

   • the femur
   • the pelvis
   • the humerus
   • the tibia
   Check

8. 8. Which bone is in the lower leg (shin)?

   • the skull
   • the pelvis
   • the femur
   • the tibia
   Check

9. 9. What does a muscle do when it contracts?

   • gets longer and pushes
   • turns into bone
   • stays the same
   • gets shorter and pulls on a bone
   Check

10. 10. What connects muscles to bones?

    • nerves
    • cartilage
    • tendons
    • ligaments
    Check

11. 11. Arun's forcemeter points at 28 on a newton scale. What is the reading?

    • 0.28 N
    • 280 N
    • 28 N
    • 2.8 N
    Check

12. 12. Which hypothesis can be tested by breaking paper straws?

    • Old bones break more easily than young bones.
    • Eating calcium makes bones stronger.
    • Thick bones are stronger than thin bones.
    • Bones grow at night.
    Check

13. 13. In the straw test of 'long bones break more easily', what would you change?

    • the force meter
    • the person pulling
    • the length of the straw
    • the colour of the straw
    Check

14. 14. What are two jobs of the skeleton?

    • digestion and breathing
    • hearing and smell
    • making food and storing light
    • support and protection
    Check

15. 15. Which organ does the skull protect?

    • the heart
    • the brain
    • the stomach
    • the lungs
    Check

16. 16. Muscles can only do one kind of force. Which?

    • They can only twist.
    • They can only pull.
    • They can push and pull.
    • They can only push.
    Check

17. 17. Which kind of joint is the shoulder?

    • a fixed joint
    • a hinge joint
    • a ball-and-socket joint
    • it is not a joint
    Check

18. 18. Why are tendons not stretchy?

    • so the muscle's pull moves the bone, not stretches the tendon
    • so they store energy
    • so they can push the bone
    • so they can grow longer
    Check