Question 1

Maslinda conducted an experiment as shown below. The plates are identical but made of different materials, C and D. She placed an identical ice cube on the top of each plate. She observed that the ice cube on material C melted first and made the statements below.
A  Material D gained heat from the ice cube.
B  Both ice cubes lost heat to the surrounding air.
C  Material C is a better conductor of heat than material D.
Which of the following statement(s) above is/are wrong?

Accepted Answer

C. A and B only. The ice cube on material C melted first, meaning material C transferred heat to the ice cube faster, so C is a better conductor (statement C is correct). Heat flows from hotter to colder objects, so the ice cubes gained heat from the materials and surrounding air; they did not lose heat (statement B is wrong). Material D also gave heat to the ice cube (the ice gained heat from D, not the other way round), so statement A is wrong. The wrong statements are A and B.

Question 2

A flowering plant goes through processes A, B and C in its life cycle as shown in the diagram below. Process B takes place before process C. Which of the following correctly represents processes A, B and C?

Accepted Answer

D. Process A: germination, Process B: pollination, Process C: fertilisation. Process A goes from seed to young plant, which is germination. The cycle from adult flowering plant back to seed requires pollination first (transfer of pollen) followed by fertilisation (fusion of male and female reproductive cells) to form seeds. So A = germination, B = pollination, C = fertilisation.

Question 3

The diagram below shows two similar plants, K and L, of the same kind. A farmer planted the seeds of plant K only on a new plot of land. After a few weeks, the planted seeds grew into new plants and produced yellow flowers only.
Based on the observation, the farmer made the following statements:
A  The new plants inherited the characteristics from plant K only.
B  The new plants inherited the characteristics from plant L only.
C  The new plants did not inherit the characteristics from both plants K and L.
Which of the following statement(s) above best explains the colour of the flowers produced?

Accepted Answer

A. A only. Only the seeds of plant K were planted, and these seeds carry the inherited characteristics of plant K. The resulting plants produced only yellow flowers, identical to plant K, showing that the new plants inherited their flower-colour characteristic from plant K. Statement A is correct; statement B is wrong (they did not inherit from L); statement C is wrong (they did inherit characteristics, just from K only). (The school answer key accepts both option (1) A only and option (3) A and C only.)

Question 4

The table below shows the characteristics of Louis and his parents. How many characteristic(s) did Louis inherit from his mother?

Accepted Answer

A. 1. Compare each characteristic of Louis to his mother. Hair: Louis curly, mother curly (match). Eyelid: Louis double, mother single (no match — matches father). Lips: Louis thin, mother thick (no match — matches father). Earlobe: Louis attached, mother detached (no match — matches father). Only 1 characteristic (curly hair) was inherited from his mother.

Question 5

Which of the following statement(s) regarding the sexual reproduction in humans is/are true?
A  The sperm cell is produced by the testes.
B  The unfertilised egg will develop in the womb.
C  The ovary produces and fertilises the eggs on its own.
D  The developing baby will obtain digested food from the mother.

Accepted Answer

B. A and D only. A is true — the testes produce sperm cells. B is false — only a fertilised egg implants and develops in the womb; an unfertilised egg is shed during menstruation. C is false — the ovary only produces egg cells; fertilisation occurs in the oviduct/fallopian tube and requires sperm. D is true — the developing baby receives digested food (and oxygen) from the mother via the placenta and umbilical cord. So A and D are true.

Question 6

The reproductive systems of humans and a flowering plant are shown in the diagram below. Which one of the following correctly shows the function of the parts of the human and plant reproductive systems?

Accepted Answer

B. Function: produces female reproductive cells — Human: E, Plant: Z. Matching each labelled part to its function: the part that produces the female reproductive cell (egg/ovum) in the human female system and the corresponding ovule-producing part in the flower (labels E and Z in this diagram) gives the correct function-to-part match according to the school answer key. The other options pair the function with the wrong labelled part.

P5 Science SA1 2023 — Nanyang

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