ZIMSEC O-Level Combined Science Paper 1 November 2025 Question Paper

About this question paper

This is the ZIMSEC O-Level Combined Science question paper for Paper 1 from November 2025. Use it for exam practice under timed conditions, then check your work against the marking scheme. The paper code is 4003/1. Time allowed: 1 hour. See the marking scheme.

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Extracted text

# ZIMBABWE SCHOOL EXAMINATIONS COUNCIL
General Certificate of Education Ordinary Level

**COMBINED SCIENCE <br> PAPER 1 Multiple Choice**

**NOVEMBER 2025 SESSION**

Additional materials:
Multiple Choice answer sheet
Soft clean eraser
Soft pencil (type B or HB is recommended)
Calculator (optional)

### INSTRUCTIONS TO CANDIDATES

Do not open this booklet until you are told to do so.
Write your name, centre number and candidate number on the answer sheet in the spaces provided unless this has already been done for you.

Answer all questions. There are forty questions in this paper.
For each question, there are four possible answers, \(\mathbf{A}, \mathbf{B}, \mathbf{C}\) and \(\mathbf{D}\).
Choose the one you consider correct and record your choice in soft pencil on the separate answer sheet.

Read very carefully the instructions on the answer sheet.

### INFORMATION FOR CANDIDATES

Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet.

**This question paper consists of 15 printed pages.**

Copyright: Zimbabwe School Examinations Council, N2025.

## Question 1
The diagram shows a plant cell.

Which part maintains the shape of the cell?

![](https://ocr.unopasa.com/p/ocr_assets/a6531b2cf711bef919739a6fa46bb40a82e1efe75317ca68da47b021c28ae590.jpg)

## Question 2
By which process does water enter root hair cells?

A osmosis

B diffusion

C active uptake

D translocation

## Question 3
Which instrument is used to measure the rate of transpiration?

A barometer

B manometer

C hydrometer

D potometer

## Question 4
The diagram shows part of the carbon cycle.

Which process, A, B, C or D, represents photosynthesis?

![](https://ocr.unopasa.com/p/ocr_assets/dbb1dfc9e180b869be013bf131ce677cf4afb98c9ffcc05822be5f220ed52960.jpg)

## Question 5
Which statement describes the structure of a blood capillary?

A It contains valves.

B It is one cell thick.

C It has a wide lumen.

D It has a thick elastic layer.

## Question 6
The digestion of protein produces

A glucose.

B glycerol.

C amino acids.

D fatty acids.

## Question 7
Which nutrient prevents constipation?

A fat

B protein

C roughage

D carbohydrate

## Question 8
The diagram shows a food web.

![](https://ocr.unopasa.com/p/ocr_assets/23d40d361a6bff33b6f4291235a8ade0184958fcf588c047f83186729bc4c970.jpg)

In the food web, the lizard is

A a carnivore.

B a herbivore.

C an omnivore.

D a decomposer.

## Question 9
Which sequence correctly shows the flow of energy in an ecosystem?

A sun ⟶ secondary consumer ⟶ primary consumer ⟶ producer

B secondary consumer ⟶ tertiary consumer ⟶ producer ⟶ sun

C producer ⟶ primary consumer ⟶ tertiary consumer → sun

D sun ⟶ producer ⟶ primary consumer ⟶ secondary consumer

## Question 10
Which substance builds up in muscles as a result of anaerobic respiration?

A oxygen

B ethanol

C lactic acid

D carbon dioxide

## Question 11
Which condition is mainly caused by tobacco smoking?

A liver cirrhosis

B emphysema

C hallucinations

D damaged muscles

## Question 12
The release of a mature ovum from the ovary into the oviduct takes place during

A menstruation.

B fertilisation.

C implantation.

D ovulation.

## Question 13
Which one is a sign of puberty in girls?

A widening of the pelvic girdle

B broadening of shoulders

C development of beard

D deepening of voice

## Question 14
Which disease is water-borne?

A bilharzia

B malaria

C herpes

D ebola

## Question 15
Which is the best method used to separate two liquids which have different densities?

A sieving

B filtration

C distillation

D decanting

## Question 16
The diagram shows apparatus that are used in paper chromatography.

![](https://ocr.unopasa.com/p/ocr_assets/4ff53813e18d45427ee919c9e9c01c3f40f85ac6fcf8835b1b4ec441725368c0.jpg)

What is the purpose of liquid Y ?

A to give colour to the dyes

B to separate the dyes

C to provide a sweet scent

D to make the paper wet

## Question 17
Which diagram, A, B, C or D, shows the electronic configuration of a chlorine atom, \({ }_{17}^{37} \mathrm{Cl}\) ?

![](https://ocr.unopasa.com/p/ocr_assets/6287fe203e671233ba0638ac4144760643c1f196f5fde52ec204f24c2a5d64b0.jpg)
A

![](https://ocr.unopasa.com/p/ocr_assets/15f936a3d88b12a74f1ac5b1499d9e65a7bf6cde91d05cd8647bdd1edd07071d.jpg)
B

![](https://ocr.unopasa.com/p/ocr_assets/d5a0f406a1d3e751f4d1bef858cac585071fba58ec78a437e205e34cee6f7bba.jpg)
C

![](https://ocr.unopasa.com/p/ocr_assets/f34e3a8fc1ac31cf99b98f20100763470ec236270f21d8d5d6710da846b4cd3c.jpg)
D

## Question 18
The element carbon exists as carbon-12, \({ }_{6}^{12} C\) and carbon-14, \({ }_{6}^{14} C\).

The two carbon atoms have

A the same number of electrons.

B the same number of neutrons.

C different number of protons.

D different chemical properties.

## Question 19
Which statement correctly describes covalent compounds?

A They are soluble in water.

B They conduct electricity.

C They generally have low melting points.

D They are usually solids at room temperature.

## Question 20
Which one is the correct formula for calculating the concentration of a solution?

A concentration \(=\frac{\text { moles }}{\text { volume }}\)

B concentration \(=\frac{\text { volume }}{\text { moles }}\)

C concentration \(=\) moles x volume

D concentration \(=\) moles + volume

## Question 21
The diagram shows the apparatus used in the electrolysis of water.

![](https://ocr.unopasa.com/p/ocr_assets/4c183c853c9227be6aaa935dac22857b01b88391c62bed5371e2b9e5b2fd77ee.jpg)

Why is the water acidified?

A to reduce its electrical conductivity

B to increase the formation of ions

C to produce fumes

D to give it scent

## Question 22
A compound

A is a mixture of substances.

B can be separated by physical means.

C has different substances that are chemically combined.

D is formed without either the gain or release of heat energy.

## Question 23
When sulphuric acid reacts with a base, the salt formed is a

A …