P4 Science CA1 2025 — Nan Hua

Q: The diagram below shows a plant. Which part helps the plant to make food?

B. B. Part A is the flower, B is the leaf, C is the stem and D is the roots. Leaves contain chlorophyll which traps light energy to make food through photosynthesis, so the leaf (B) is the part that helps the plant make food.

Q: Diana wanted to carry out an experiment to find out if the amount of water given to a plant will affect its growth. She listed some of the variables of the experiment below. J Type of plant K Amount of water given to each plant L Amount of light given to each plant M Height of each plant at the end of the experiment Which of the variables should she keep the same to ensure that the experiment is fair?

B. J and L only. K (amount of water) is the variable being tested (independent variable) so it must be changed. M (height of plant) is the result being measured (dependent variable). To ensure a fair test, all other variables — J (type of plant) and L (amount of light) — must be kept the same.

Q: The table below shows how some parts of the human body are classified. Which part is placed in the wrong group?

C. windpipe. The windpipe (trachea) is part of the respiratory system, not the skeletal system. Heart and blood vessels correctly belong to the circulatory system, muscles to the muscular system, and the skull correctly belongs to the skeletal system.

Q: Which of the following represents the function(s) of the stomach?

C. Digest food: ✓; Absorb digested food into blood: X; Transport digested food to other parts of the body: X. The stomach digests food (✓) by breaking it down with digestive juices. It does NOT absorb digested food into the blood (X) — that occurs in the small intestine. It also does NOT transport digested food around the body (X) — that is the role of the circulatory system.

Q: The diagram below shows what happens to the food we eat when it enters our body. Which statement(s) is/are true? P Substance C is water. Q All food that enters system A will be absorbed. R Digested food enters system B through the walls of the large intestine.

A. P only. System A is the digestive system, which splits food into digested food (goes to System B, the circulatory system) and undigested food. Water (Substance C) is reabsorbed from the undigested food in the large intestine, so P is true. Q is false because undigested food is not absorbed. R is false because digested food is absorbed through the walls of the small intestine, not the large intestine.

P4 Science 2025 CA1 8 questions 20 marks

Source: Nan Hua, 2025

This P4 Science CA1 paper from Nan Hua (2025) contains 8 questions worth 20 marks. Use it as a study reference for Science topics typically tested at P4 level in Singapore schools.

Q1 MCQ 2 marks 🖼 Visual

The diagram below shows a plant. Which part helps the plant to make food?

Q2 MCQ 2 marks

Diana wanted to carry out an experiment to find out if the amount of water given to a plant will affect its growth. She listed some of the variables of the experiment below. J Type of plant K Amount of water given to each plant L Amount of light given to each plant M Height of each plant at the end of the experiment Which of the variables should she keep the same to ensure that the experiment is fair?

Q3 MCQ 2 marks 🖼 Visual

The table below shows how some parts of the human body are classified. Which part is placed in the wrong group?

Q4 MCQ 2 marks 🖼 Visual

Which of the following represents the function(s) of the stomach?

Q5 MCQ 2 marks 🖼 Visual

The diagram below shows what happens to the food we eat when it enters our body. Which statement(s) is/are true? P Substance C is water. Q All food that enters system A will be absorbed. R Digested food enters system B through the walls of the large intestine.

Q6 Structured 3 marks 🖼 Visual

Devi carried out an experiment with three similar plants, X, Y and Z, in a well-lit room. She removed some roots from plant Y and all the roots from plant Z. After one day, Devi measured the amount of water left in each set-up and recorded the results in the table below. Set-up X: Amount of water given 500 mL, Amount of water left 360 mL. Set-up Y: Amount of water given 500 mL, Amount of water left 420 mL. Set-up Z: Amount of water given 500 mL, Amount of water left 480 mL. (a) What is the aim of the experiment? [1] (b) Which plant took in the most amount of water? Explain why. [1] (c) Devi planted plant Z in the soil of her garden. After a heavy rain, plant Z was washed away. Explain why. [1]

Q7 Structured 3 marks

(a) Name the part(s) of the human respiratory system. [1] (b) State the function of the human respiratory system. [1] (c) Name the human system that carries substances around the body. [1]

Q8 Structured 4 marks 🖼 Visual

(a) State what digestion is. [1] The diagram below shows the human digestive system. The graph below shows the amount of undigested food leaving each part A, B, C, D and E after a meal. Parts B and E have been labelled. (b) Fill in the remaining boxes with parts A, C and D. [1] (c) Jane's mother advised her to chew her food more times before swallowing. Explain how that will help in the digestion of the food. [2]

P4 Science CA1 2025 — Nan Hua

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