ZIMSEC O-Level Combined Science Paper 1 November 2021 Question Paper

NOVEMBER 2021 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.

There are forty questions in this paper. Answer all questions. For each question, there are four possible answers, A, B, C and 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.

Question 1

The bar graph shows the variation in mass for a swarm of locusts.

What is the total number of locusts?

A 2

B 8

C 19

D 50

Question 2

The diagram shows a section through a plant root.

Which tissue, A, B, C or D, transports water?

Question 3

Osmosis is the movement of water molecules from their region of

A high concentration to low concentration through a fully permeable membrane.

B low concentration to high concentration through a fully permeable membrane.

C high concentration to low concentration through a selectively permeable membrane.

D low concentration to high concentration through a selectively permeable membrane.

Question 4

What is the difference between green plants and animals?

A animals respire but plants do not

B plants respire but animals do not

C animals manufacture their own food but plants do not

D plants manufacture their own food but animals do not

Question 5

Which are the products of photosynthesis?

A oxygen and water

B glucose and oxygen

C carbon dioxide and water

D glucose and carbon dioxide

Question 6

What is produced when proteins are digested?

A amino acids

B fatty acids

C glycerol

D maltose

Question 7

The diagram shows the human respiratory system.

Which part, A, B, C or D, is the alveolus?

Question 8

Which component of blood carries dissolved nutrients?

A plasma

B platelets

C red blood cells

D white blood cells

Question 9

The diagram shows a bean seed.

Which part, A, B, C or D, stores food?

Question 10

The diagram shows a flower.

Which parts of the flower make up the stamen?

A 1 and 2

B 3 and 4

C 3 and 5

D 1 and 5

Question 11

Personal hygiene involves

A covering one's food.

B brushing one's teeth.

C cleaning one's room daily.

D keeping active through exercise.

Question 12

Which one is not an advantage of biodiversity in a natural ecosystem?

A interdependence

B more disease spreading

C wide variety of food

D self sustenance of an ecosystem

Question 13

Which organ produces sperms?

A the testis

B the penis

C the epididymis

D the prostate gland

Question 14

Which stage of the mosquito life cycle is controlled by spraying insecticides?

A egg

B pupa

C larva

D adult

Question 15

Which one is an application of filtration?

A grain separation

B salting peanuts

C treatment of water

D formation of sugar crystals

Question 16

Which characteristic increases when more salt is dissolved in a fixed volume of water?

A solubility

B concentration

C volume of solvent

D colour of solvent

Question 17

The diagram shows the changes of state.

Which change of state, A, B, C or D, occurs when iodine crystals are heated?

Question 18

Magnesium and calcium are in Group II of the Periodic Table.

They have the same number of

A protons.

B neutrons.

C electron shells.

D valency electrons.

Question 19

What is electrolysis?

A breaking down of an ionic compound using electricity

B breaking down of a covalent compound using electricity

C breaking down of an ionic compound using heat

D breaking down of a covalent compound using heat

Question 20

The reaction between sodium and hydrochloric acid produces a salt and

A hydrogen.

B oxygen.

C chlorine.

D water.

Question 21

Iron rusts in the presence of moisture and

A argon.

B oxygen.

C nitrogen.

D hydrogen.

Question 22

Zinc oxide and sulphuric acid react according to the equation:

$$ \mathrm{ZnO}+\mathrm{H}_{2} \mathrm{SO}_{4} \rightarrow \mathrm{ZnSO}_{4}+\mathrm{H}_{2} \mathrm{O} $$

What type of reaction is shown by the equation?

A addition

B condensation

C elimination

D neutralisation

Question 23

Which one is a use of sulphuric acid?

A manufacture of ammonia

B nitric acid production

C manufacture of household cleaners

D cleaning materials before electroplating

Question 24

Which substance is reacted with sodium hydroxide to form soap?

A water

B fatty acids

C sodium chloride

D amino acids

Question 25

Which one is an equation for the production of biogas?

A methane + carbon dioxide $\xrightarrow{\text{fermentation}}$ organic waste

B carbon dioxide + water + energy $\xrightarrow{\text{fermentation}}$ organic waste

C organic waste $\xrightarrow{\text{fermentation}}$ methane + carbon dioxide

D organic waste $\xrightarrow{\text{fermentation}}$ carbon dioxide + water + energy

Question 26

Which one is not an effect of burning fuels?

A afforestation

B pollution

C acid rain

D global warming

Question 27

Which molecular formula represents ethanol?

Question 28

A metre has

A $10 \mathrm{~mm}$.

B $100 \mathrm{~mm}$.

C $1000 \mathrm{~mm}$.

D $10000 \mathrm{~mm}$.