Biology · Unit 7

Skeleton and Bones

Bones, joints and the skeleton

Bone is the part of the body most people picture as inert, which is exactly backwards. It is living tissue with a blood supply, it remodels itself continuously in response to load, and it is where blood cells are made.

The unit covers the skeleton's structure and its jobs - support, movement, protection, mineral storage, blood production - along with joint types and what actually happens inside a bone as it grows and repairs.

This unit breaks down into 20 short steps and 120 questions, starting at difficulty 1 and building to 3. Below you can see exactly what it covers, how the path is structured, and worked examples with explanations.

Steps: 20
Questions: 120
Difficulty: 1-3

What this unit covers

Bones and the Skeleton
Joints and Movement
Inside a Bone
Jobs of the Skeleton
Bone Growth and Health

Where this fits

Pairs naturally with the muscular content in Human Body Systems. Nothing else depends on it, so it can be taken whenever.

Where people slip

Joints are classified by how much movement they allow, not by where they are. The skull has joints; they simply do not move.

How the unit is structured

Skeleton and Bones runs as 20 short steps that unlock in order. 15 are practice rounds and 5 are challenge rounds that pull together everything before them. Questions start at difficulty 1 and climb to 3 as you progress.

Step 1 · easierStep 20 · harder

Challenge rounds

Example questions

30 real questions from this unit, with the answer and the reason behind it, grouped by what they practise. There are 120 in the unit altogether.

Bone Growth and Health

Multiple choiceLevel 1
1. Which nutrient, found in milk and cheese, helps build strong bones?
- Calciumcorrect
- Sugar
- Salt
- Fat
Calcium is a mineral in dairy foods that helps keep bones strong.
True or falseLevel 1
2. Regular exercise helps make bones stronger.
Answer: True
Weight-bearing exercise puts healthy stress on bones, encouraging them to grow denser and stronger.
Fact or fibLevel 2
3. As a child grows, soft cartilage is slowly replaced by hard bone.
Answer: True
Much of a young child's skeleton starts as cartilage, which gradually turns into bone in a process called ossification.
Sequence recallLevel 2
4. Put the stages of a broken bone healing in the correct order.
Answer: Bone breaks -> Blood clot forms -> Soft callus forms -> New bone hardens
A broken bone first bleeds and forms a clot, then a soft callus, which is slowly replaced by new hard bone.
Sort into groupsLevel 2
5. Sort each habit into whether it is good or bad for your bones.
Answer: Drinking milk = Good for bones; Regular exercise = Good for bones; Smoking = Bad for bones; Very little calcium = Bad for bones
Calcium-rich food and exercise strengthen bones, while smoking and too little calcium weaken them.
Fill the blankLevel 3
6. Growth in the length of a long bone happens at the epiphyseal ____, which turns fully to bone once a person stops growing.
- platecorrect
- marrow
- canal
- membrane
The epiphyseal plate (growth plate) is cartilage that lengthens the bone and then ossifies when growth ends.

Bones and the Skeleton

Guess the numberLevel 1
7. How many bones are there in a fully grown adult human skeleton?
Answer: 206 bones
The adult human skeleton is made up of 206 bones.
Multiple choiceLevel 1
8. Which is the longest bone in the human body?
- The femur (thigh bone)correct
- The humerus (upper arm)
- The spine
- The skull
The femur, or thigh bone, is the longest and strongest bone in the body.
Build the sentenceLevel 2
9. Build the phrase naming the two bones of the forearm.
Answer: radius and ulna
The forearm contains the radius on the thumb side and the ulna on the little-finger side.
Fill the blankLevel 2
10. Insects and crabs support and protect their bodies with a hard outer covering called an ____.
- exoskeletoncorrect
- endoskeleton
- endosteum
- exocarp
An exoskeleton is a hard external skeleton, such as the shell of a crab or the tough casing of an insect.
Match the pairsLevel 2
11. Match each bone to its everyday name.
Answer: Clavicle = Collarbone; Sternum = Breastbone; Scapula = Shoulder blade; Coccyx = Tailbone
The clavicle is the collarbone, the sternum the breastbone, the scapula the shoulder blade and the coccyx the tailbone.
Odd one outLevel 2
12. Which of these is NOT part of the axial skeleton?
- Femurcorrect
- Skull
- Ribs
- Spine
The femur belongs to the appendicular skeleton (the limbs); the skull, ribs and spine are all axial.

Inside a Bone

Fill the blankLevel 1
13. The soft tissue found in the middle of many bones is called bone ____.
- marrowcorrect
- muscle
- cartilage
- skin
Bone marrow fills the hollow centre of many bones.
Choose all that applyLevel 2
14. Which of these are really found inside your bones? (Choose all that apply.)
- Calciumcorrect
- Collagencorrect
- Living bone cellscorrect
- Chlorophyll
Bones contain the mineral calcium, the protein collagen and living bone cells; chlorophyll is only found in plants.
Multiple choiceLevel 2
15. Which part of a bone makes new blood cells?
- Red bone marrowcorrect
- Compact bone
- Cartilage
- Tendon
Red bone marrow inside some bones produces new red and white blood cells.
Tap the pairsLevel 2
16. Match each part of a bone to what it does.
Answer: Compact bone = Hard, dense outer layer; Spongy bone = Light inner layer with holes; Red marrow = Makes blood cells; Periosteum = Membrane covering the bone
A bone has a hard compact outer layer, lighter spongy bone inside, marrow that makes blood cells, and a covering membrane.
Odd one outLevel 3
17. Three of these are types of cartilage found in the body. Which one is the odd one out?
- Keratincorrect
- Hyaline cartilage
- Fibrocartilage
- Elastic cartilage
Keratin is the protein in hair and nails, not a cartilage; hyaline, fibro- and elastic cartilage are the three cartilage types.
Sort into groupsLevel 3
18. Sort each body part by the type of cartilage it is made from.
Answer: End of a bone in a joint = Hyaline cartilage; Rings of the windpipe = Hyaline cartilage; Disc between two vertebrae = Fibrocartilage; The knee's meniscus = Fibrocartilage; The outer ear = Elastic cartilage; The epiglottis = Elastic cartilage
Hyaline cartilage lines joints and the windpipe, tough fibrocartilage cushions the spine and knee, and elastic cartilage shapes the ear and epiglottis.

Jobs of the Skeleton

Build the sentenceLevel 1
19. Build a sentence about one job of the skeleton.
Answer: The skeleton gives the body support and shape
A key job of the skeleton is to give the body support and shape.
Fill the blankLevel 1
20. Bones cannot move by themselves; they are pulled by ____ to move the body.
- musclescorrect
- nerves
- veins
- skin
Muscles pull on bones to create movement at the joints.
Multiple choiceLevel 1
21. Which organ does the skull protect?
- The braincorrect
- The liver
- The kidneys
- The bladder
The skull forms a hard case around the brain to keep it safe.
Odd one outLevel 1
22. Which of these is NOT a job of the skeleton?
- Digesting foodcorrect
- Supporting the body
- Protecting organs
- Allowing movement
Digesting food is the job of the digestive system, not the skeleton.
Choose all that applyLevel 2
23. Which of these are real jobs of the skeleton? (Choose all that apply.)
- Supporting the bodycorrect
- Protecting organscorrect
- Making blood cellscorrect
- Producing sound
The skeleton supports the body, protects organs and helps make blood cells, but it does not make sound.
Guess the numberLevel 3
24. Roughly what percentage of the body's calcium is stored in the bones and teeth?
Answer: 99 %
About 99 percent of the body's calcium is locked in the bones and teeth, which act as the body's main calcium store.

Joints and Movement

Multiple choiceLevel 1
25. What type of joint is the knee?
- Hinge jointcorrect
- Ball-and-socket joint
- Pivot joint
- Fixed joint
The knee is a hinge joint, which lets the leg bend and straighten like a door hinge.
Fact or fibLevel 2
26. The elbow is a ball-and-socket joint.
Answer: False
The elbow is actually a hinge joint; it can only bend and straighten, not rotate freely.
Fill the blankLevel 2
27. Smooth, rubbery ____ covers the ends of bones so they do not rub together in a joint.
- cartilagecorrect
- marrow
- tendon
- enamel
Cartilage cushions the ends of bones and lets them move smoothly.
Match the pairsLevel 2
28. Match each type of joint to an example in the body.
Answer: Hinge joint = Knee; Ball-and-socket joint = Shoulder; Pivot joint = Neck; Fixed joint = Skull
Different joints allow different movements, from the hinge of the knee to the free rotation of the shoulder.
Choose all that applyLevel 3
29. Which of these are structures found in a typical synovial joint?
- Synovial fluidcorrect
- Articular cartilagecorrect
- Joint capsulecorrect
- Red bone marrow
- Osteon (Haversian system)
Synovial joints contain synovial fluid, articular cartilage and a fibrous joint capsule; red marrow and osteons are parts of bone tissue, not the joint.
Odd one outLevel 3
30. Three of these are forms of joint arthritis. Which one is the odd one out?
- Osteoporosiscorrect
- Osteoarthritis
- Rheumatoid arthritis
- Gout
Osteoporosis is a loss of bone density, not a joint arthritis; osteoarthritis, rheumatoid arthritis and gout all affect the joints.

Where these questions come from. Each unit starts as a plan of the concepts it should cover and the difficulty it should span. Questions are written against that plan with AI assistance, then checked by a validator that rejects anything without a single defensible answer, an explanation, or plausible wrong options. How we write questions sets out the whole process, and corrections are fixed in the bank and reach the site and the app the same day.

How you practise

This unit mixes 17 different question formats, so you are recalling and applying rather than recognising the same layout every time.

Build the sentence
Choose all that apply
Fact or fib
Fill the blank
Guess the number
Listen and choose
Match the pairs
Multiple choice
Odd one out
Picture question
Put in order
Sequence recall
Sort into groups
Spell it
Tap the pairs
True or false
Type the answer

Practise Skeleton and Bones

120 questions across 20 steps. Start with step one and crawl at your own pace.

Play this unit

Read about Skeleton and Bones

Explainers from our blog on what this unit covers. Each one ends with real questions from the bank.

How Bones and Joints Create MovementBones provide support, joints allow movement and muscles pull on the skeleton through tendons. Understanding how these parts work together makes everyday actions easier to explain.August 5, 2026 · 5 min read

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