Animals

Support systems in animals

The human skeleton supports the body, protects organs, lets muscles move the bones, stores minerals and makes blood cells.

CAPS

Grade 10 · Life Sciences · Animals

Life Sciences is two papers. Use the strand to know which one.

  • Where it is examined

    Grade 10 is the chemistry of life, cells, tissues, organs, support and transport, and the biosphere, biodiversity and the history of life.

  • How to write it

    Name the structure, then say what it does. A labelled diagram only scores if the labels are the biological names. “It helps the body” is not a function.

  • How a marker reads it

    A common mix-up is to say muscles push, or that ligaments and tendons are the same strap.

A 2-mark “explain” wants two facts, or one fact and its reason. Extra sentences that contradict the first one can cancel a mark.

RL

Diagram

Worked theory

Worked theory. Bending the elbow. The biceps contracts and pulls the forearm up. The triceps is relaxed. To straighten the arm the triceps pulls and the biceps lets go. The elbow is a hinge, so the forearm does not spin like a shoulder. The skull is not a joint for movement. It is a case that protects the brain. A broken bone can heal because bone is living tissue, not dry plastic.

More worked examples

  • A soccer kick

    The hip is a ball-and-socket, so the thigh can swing in several directions. The knee is a hinge, so the lower leg only folds and straightens. To straighten the knee for the kick, the quadriceps pulls. The hamstrings let go. After the kick the hamstrings pull and the knee bends again. The quadriceps cannot push the knee straight. No muscle pushes.

  • Lifting a school bag

    To bend the elbow and lift a bag, the biceps contracts and the triceps lets go. To straighten the arm and put the bag down, the triceps contracts and the biceps lets go. Neither muscle can push. The humerus is the lever they pull on. A learner who says the biceps both lifts and straightens has given one muscle two opposite jobs. The pair is the system.

In ordinary words

Bone is living tissue with calcium salts for hardness. Joints are where bones meet: a hinge, like the knee, bends one way; a ball-and-socket, like the shoulder, turns in many directions. Cartilage cushions. Ligaments hold bone to bone. Tendons hold muscle to bone. Muscles only pull. A pair of muscles works against each other so a limb can bend and straighten.

In South Africa

A netballer’s knee hinge and shoulder socket are the two joints in one game.

Part 1 / 4

What it is

The human skeleton supports the body, protects organs, lets muscles move the bones, stores minerals and makes blood cells.

Diagram
Diagram

More worked examples

Board walkthroughs on this topic. Open one, copy the working, then try the next.

Example 1 / 20

Classify these joints: knee, shoulder, skull sutures, between vertebrae.

How we got there

Read this like a teacher at the board. We go slowly, name every number, and say why we take each step.

Explain in another language · 11

1. What is the question asking?

Read the question twice. Circle the unknown. Underline every number and unit. The paper is asking: Classify these joints: knee, shoulder, skull sutures, between vertebrae.

In other words — as if you have never seen this before

If you have never seen this before: Joints are immovable, slightly movable or freely movable (synovial). We will name a method in words, write the formula with no numbers, then substitute one line at a time.

2. What do we already know?

Four joints.

3. Which method — and why this one?

Joints are immovable, slightly movable or freely movable (synovial).

4. Step-by-step working

  1. 01 / 07

    Step A — Read the question twice

    Slow down. Circle the word that names the unknown. Underline every number and its unit. Do not grab a formula yet — first decide what the paper is actually asking.

    Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

  2. 02 / 07

    Step B — Write the given in a column

    Four joints.

    Why this step: A column with units stops you mixing cm with m, or minutes with seconds. Markers can also see you started correctly.

  3. 03 / 07

    Step C — Name the method in words

    Joints are immovable, slightly movable or freely movable (synovial).

    Why this step: If you can say the method in a sentence, you will pick the right formula. First-timers skip this and grab the first equation they remember.

  4. 04 / 07

    Identify the given

    Knee: hinge synovial. Shoulder: ball-and-socket synovial. Skull sutures: immovable (fibrous). Vertebrae: slightly movable (cartilaginous).

    Why this step: We only do one job per line so a marker can follow the marks — and so you can find a slip without starting over.

  5. 05 / 07

    Step G — Sense-check the size

    Ask: is this the kind of number a Grade 10–12 paper would want? A speed of 3 000 ms for a learner walking, or a probability bigger than 1, means a unit or algebra slip. Estimate first: round the numbers and do the sum in your head.

    Why this step: Markers write ‘unrealistic’ in the margin when the method is right but the size is wild. A 10-second head check often finds a missing 10² or a unit that never changed.

  6. 06 / 07

    Step F — Box the answer with its unit

    Knee — hinge; shoulder — ball and socket; skull — immovable; vertebrae — slightly movable.

    Why this step: A number without a unit is half a mark on a Physics paper, and a marker can miss a Maths answer that is buried in working.

  7. 07 / 07

    Step H — What the marker is looking for

    On an NSC memo you usually earn: (1) a method mark for naming the right formula or idea in words, (2) an accuracy mark for substituting the given numbers with units, (3) an accuracy mark for the boxed answer with its unit. Write those three lines even if you are unsure of the arithmetic — blank pages score zero.

    Why this step: First-timers chase the final number and leave the method blank. The memo still pays out for the idea and the substitution even when the last line is wrong.

5. The answer

Knee — hinge; shoulder — ball and socket; skull — immovable; vertebrae — slightly movable.

Copy onto your answer sheet — in this order

Answer: Knee — hinge; shoulder — ball and socket; skull — immovable; vertebrae — slightly movable.

6. Check it like a marker

Synovial joints have synovial fluid and cartilage.

7. A trap first-timers fall into

First-timers often grab the first formula they remember, mix units (cm with m, minutes with seconds), or drop a minus sign. Write the formula in words first: “this equals that, because…”

Ntsako · fx-991ZA PLUS. Tap to calculate.