Question 1

Sarah recorded the time taken for 500ml of water to boil when it was placed in three containers of different materials, X, Y and Z, in the table shown below. She needed two different containers, one to keep her orange juice cold and another one to keep her chicken soup hot, for as long as possible. Which materials would be the most suitable for making each container?

Accepted Answer

D. Z (orange juice cold) / Z (chicken soup hot). Z took the longest time (15 min) for water to start boiling, indicating it is the poorest conductor of heat (best insulator). The best insulator is most suitable for both keeping cold drinks cold (preventing heat gain) and keeping hot soup hot (preventing heat loss). Therefore Z should be used for both containers.

Question 2

Jeremy found 4 flowers, A, B, C and D, similar to the one shown below, from the same plant in his garden. He then removed different parts from the 4 flowers as shown below. Which of these flowers, A, B, C or D, will definitely not be able to develop into a fruit?

Accepted Answer

A. B only. For a flower to develop into a fruit, the ovary (female reproductive part) must be present so that fertilisation can occur and the ovary can develop into the fruit. Flower B has its ovary/pistil removed (only stamens remain), so it definitely cannot develop into a fruit. Flowers A, C and D still retain the ovary, so they can potentially develop into fruits if pollinated.

Question 3

W, X, Y and Z represent the processes that all flowering plants go through during reproduction. W: pollination. X: fertilisation. Y: germination. Z: seed dispersal. Which of the following diagrams shows the correct order of the four processes?

Accepted Answer

D. Cycle: Y → Z → X → W → Y. The correct order of reproduction in flowering plants is: pollination (W) → fertilisation (X) → seed dispersal (Z) → germination (Y) → (new plant which then undergoes pollination again). Option 4 shows the cycle Y → Z → X → W → Y, but read in the correct direction around the loop it gives W → X → Z → Y → W, which matches the proper sequence: pollination, fertilisation, seed dispersal, germination.

Question 4

Which two of the following are characteristics that are not passed down from parents to their young? A. Length of hair. B. Type of earlobe. C. Length of fingernails. D. Ability to roll the tongue.

Accepted Answer

A. A and C. Inherited characteristics are passed down genetically from parents to offspring (e.g., type of earlobe and ability to roll the tongue). Length of hair and length of fingernails are not inherited — they depend on how often a person cuts their hair or nails, which is a lifestyle choice, not a genetic trait.

Question 5

The diagrams below show the human female and male reproductive systems. Which of the following correctly matches the parts its function.

Accepted Answer

C. P produces eggs / U produces sperms. In the female reproductive system, P labels the ovaries, which produce eggs. In the male reproductive system, U labels the testes, which produce sperms. Therefore the correct match is P produces eggs and U produces sperms.

Question 6

The diagrams below show the human and plant reproductive systems. Which one of the following statements is correct?

Accepted Answer

C. Parts B and Y store female reproductive cells.. In the human reproductive system, B labels the ovary, which stores female reproductive cells (eggs). In the plant reproductive system, Y labels the ovary, which stores female reproductive cells (ovules). Therefore B and Y both store female reproductive cells, making option (3) correct.

P5 Science CA1 2021 — Nanyang

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