Question 1

Mark placed an ice cube onto a metal spoon as shown in the diagram below. After some time, he noticed that the ice cube had melted and the metal spoon felt cold. Which of the following statements correctly explains why Mark felt that the metal spoon was cold?

Accepted Answer

(3) The metal spoon gained heat from his fingers and lost heat to the ice cube.. Heat always flows from a region of higher temperature to a region of lower temperature. When Mark holds the metal spoon, heat flows from his warmer fingers to the colder metal spoon, making his fingers feel cold. The metal spoon, in turn, transfers heat to the ice cube, causing the ice cube to melt. Therefore, the metal spoon gained heat from his fingers and lost heat to the ice cube.

Question 2

The table below shows the characteristics of Nadia and her parents. How many characteristics was/were passed down from Nadia's mother to Nadia?

Accepted Answer

(2) 2. Comparing Nadia's characteristics with her mother's:
- Presence of dimples: Nadia (Has dimples), Mother (No dimples) - Not passed down from mother.
- Length of hair: Nadia (Short), Mother (Short) - Passed down from mother.
- Type of eyelid: Nadia (Double), Mother (Single) - Not passed down from mother.
- Type of earlobe: Nadia (Detached), Mother (Detached) - Passed down from mother.
Thus, 2 characteristics (Length of hair and Type of earlobe) were passed down from Nadia's mother to Nadia.

Question 3

Why is sexual reproduction in living things important?
A: It ensures continuity of their own kind.
B: It ensures the number of living things will decrease.
C: It ensures that all observable characteristics are passed on from parents to young.

Accepted Answer

(2) A only. A: Sexual reproduction ensures the survival and continuation of a species, thus maintaining the continuity of their own kind. This is true.
B: Sexual reproduction helps maintain or increase population numbers, not decrease them. This is false.
C: Sexual reproduction leads to genetic variation, meaning offspring inherit a mix of characteristics from both parents, but not necessarily *all* observable characteristics, and new combinations can arise. This is false.
Therefore, only statement A is correct.

Question 4

A plant undergoes processes Y and Z, as shown in the diagram below. Which of the following correctly represents processes Y and Z?

Accepted Answer

(4) Fertilisation, Germination. Process Y represents the development from a 'Flower' to a 'Seed'. This stage involves fertilization, where the male and female gametes fuse to form a zygote, which develops into an embryo within the seed.
Process Z represents the development from a 'Seed' to a 'Young plant'. This stage is germination, where the seed sprouts and grows into a seedling.
Therefore, Y is Fertilisation and Z is Germination.

Question 5

Study the flowchart below. Which of the following correctly identifies organs A, B, C and D?

Accepted Answer

(2) Ovary, Womb, Testis, Penis. Following the flowchart:
- A: Found in females ('Yes') AND produces eggs ('Yes') = Ovary.
- B: Found in females ('Yes') AND does NOT produce eggs ('No') = Womb (or Uterus).
- C: NOT found in females ('No') AND produces sperms ('Yes') = Testis.
- D: NOT found in females ('No') AND does NOT produce sperms ('No') = Penis (a male reproductive organ but does not produce sperms).
Thus, A=Ovary, B=Womb, C=Testis, D=Penis.

Question 6

The diagram below shows the reproductive parts of a flower and a human. Which one of the following statements about the reproductive parts of a flower and a human is true?

Accepted Answer

(4) Part R develops into a fruit and Part Z is where the foetus develops.. Let's identify the parts:
Flower: P (Anther), Q (Stigma), R (Ovary).
Human: Y (Ovary), Z (Uterus).

(1) Pollination occurs at Q (stigma) in a flower, but Z (uterus) is in humans and is where a foetus develops, not where pollination occurs. False.
(2) P (anther) produces pollen (male gametes). Y (human ovary) produces eggs (female gametes). They have different functions. False.
(3) Y (human ovary) contains female reproductive cells (eggs). Q (stigma) receives pollen, but the female reproductive cells in a flower are located in the ovules within the ovary (R). False.
(4) R (flower ovary) develops into a fruit after fertilization. Z (human uterus) is indeed where the foetus develops. True.

P5 Science CA1 2025 — Nanyang

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