Combined Science Practice Questions.
Combined Science practice questions for Zimsec O’level Students. I have divided them into sections in which they belong. I will upadate the answers and explanations later on.
Biology Section questions
- Why is photosynthesis an important process to all living organisms?
- Write a word equation to summarise the process of photosynthesis.
- By means of a simple labelled diagram and full experimental details, describe an experiment to show one of the conditions necessary for photosynthesis to occur.
- State five ways in which a leaf is adapted for photosynthesis.
- Draw a simple diagram showing a transverse section through a leaf and label the following parts:
- Epidermis layer
- Vascular tissue
- Draw a fully labelled diagram of the alimentary canal and state the functions of five of the labelled parts.
- Copy and complete table 2.6, on products of digestion and their use.
|Nutrient||End product of digestion||Use|
- Distinguish between absorption and assimilation.
- How is the gut adapted to facilitate absorbtion?
- Tabulate the differences between inhaled and exhaled air.
- How is the alveolus adapted for gaseous exchange?
- Why is respiration important to all living organisms?
- Which gas is used as evidence that respiration has occurred. Describe a test for the gas you named.
- Describe an experiment to show either production of carbon dioxide or energy by one of the following: green plants, germinating seeds or small animal.
- State the functions of any five of the human respiratory organs.
- Distinguish between diffusion and osmosis. Which process facilitates mineral ion uptake into the plant?
- Why is transpiration an important process in plants?
- What conditions can favour an increase in the rate of transpiration?
- Explain how the plant leaves are adapted to reduce water loss.
- State four characteristics of wind pollinated flowers.
- State the functions of the following parts of a seed:
- State the conditions necessary for germination.
- What do you understand by the term variation?
- Distinguish between continuous and discontinuous variation, giving two examples of each in plants and animals.
- When determining water content in soil a sample, why is the soil dried over a hot water bath than directly over the burner?
- The following are results from the experiment on heating the soil directly over a burner.
- Mass of container = 60g
- Mass of container + fresh soil = 100g
- Mass of container + soil after heating over water bath = 96,5g
- Mass of container + soil after direct heating = 83,5g
Calculate the percentage of water and the percentage of humus in the soil sample.
27. State the importance of each physical and biological component of soil.
28. Define a balanced diet.
29. List the components of a balanced diet and for each state its use(s) and two food sources.
30. State the importance of breast-feeding.
31. Copy and complete table
|Nutrient||Reagent(s)||Observations||Is nutrient present or absent|
- Describe the types of teeth and their functions of teeth.
- Describe the proper care of teeth.
- What causes malaria?
- Describe the main symptoms of malaria.
- How can malaria be controlled and treated?
- What is the causative agent for cholera?
- State the symptoms of cholera.
- How can cholera be controlled and treated?
- What are the body’s defence mechanisms?
- Distinguish between:
- HIV and AIDS.
- Active and passive immunity.
- Naturally and artificially acquired immunity.
- How does an infant acquire immunity?
- Draw a fully labelled diagram of either the human male or female reproductive system and state the functions of the five labelled parts.
- What are the differences and similarities between the sperm and the ovum?
- Where in humans does fertilisation occur?
- Where does ovulation occur in humans?
- What is implantation?
- What is the purpose of the menstrual cycle in women and why does it stop during pregnancy?
- State four methods of contraception and for each method, give three advantages and three disadvantages.
- For any three sexually transmitted diseases (STIs) you have studied, state the causative agent, signs and symptoms, treatment, prevention and control.
- In what ways does AIDS differ from Syphilis?
Chemistry Section Revision
- Name the three states of matter.
- Explain using the kinetic theory, the changes observed when ice is heated to a high temperature.
- Describe an atom.
- Name the sub-atomic particle that:
- Has a positive charge.
- Is found in the shells.
- Describe the nucleus of an atom.
- Draw an atom show the location of the nucleus, protons, electrons, and neutrons.
- Define an element.
- Give an example of a metallic element and a non-metallic element.
- Give two differences between a compound and a mixture.
- Write an equation for the chemical reaction that occurs between magnesium and air to produce magnesium oxide.
- State two elements that conduct electricity.
- Give one use for each of the elements:
- Name the salt formed when iron reacts with sulphuric acid.
- Name the metal and acid that react to produce zinc nitrate.
- Define oxidation in terms of oxygen gain or loss.
- Write equations for the reactions that in the blast furnace and name the substances that are oxidised and reduced.
- What is produced when sulphuric acid reacts with ammonia?
- What is the function of universal indicator?
- What colour is litmus in:
- Ammonia solution?
- Sodium hydroxide solution?
- Name two alloys of iron and state a use for each.
- State two uses of copper and explain why it is preferred over iron.
- Name the raw materials for the contact process.
- Why is sulphur trioxide not added directly to water in the contact proccess?
- State the reactants and products in the Haber process.
- Describe an industrial manufacture for one of the reactants in the Haber process.
- Draw a labelled diagram for the electrolysis of water.
- What substances are removed as solids at -55⁰C during the liquefaction of air?
- List the states in which fuel can be found.
- State the occurrence of coal in Zimbabwe and name the place where coal is mined.
- State the factors affecting:
- Biogas production
- Ethanol production
- State three uses of each of the following :
- Carbon dioxide
- Which fuel between the following pairs produce more energy?
- Charcoal and coke
- Diesel and ethanol
- Biogas and hydrogen
- Write word equations to show complete and incomplete combustion when petrol blend (fuel) is burnt in plentiful air and in very limited air.
- State the dangers of incomplete combustion.
Physics Section Questions
- State the four strokes in a petrol engine and describe the operations of any two of the strokes.
- What is the function of the carburettor?
- Describe the effects of:
- Blocked filters.
- Worn out jets.
- Sticky choke control.
- Give two advantages of multiple cylinders in an engine.
- Give the differences between a diesel engine and a petrol engine.
- Distinguish between renewable and non-renewable sources of energy.
- Give two examples of both renewable and non-renewable sources of energy.
- Describe the social and economic implications of using fuels.
- Describe how charges are produced.
- State the action between like and unlike charges.
- State the dangers of lightning.
- The production of lightning.
- The principle of a lightning conductor.
- State precautions one must take against lightning.
- Explain what is meant by:
- Voltage (V)
- Current (I)
- Name the instrument used to measure the following and give the unit for each.
- Calculate the current and hence power drawn from a power source where voltage is 210V when passing a current through a resistor of 30Ω.
- State Ohm’s Law.
- A 12V battery is supplying a current to two resistors in parallel of resistance ⅓ Ω and ⅟2Ω.
- Draw a fully labelled circuit diagram to show the above connections.
- Calculate the total current flowing in the circuit.
- State the unit of charge.
- Explain/Describe the arrangement of cells to give:
- Higher current
- Higher voltage
- Distinguish between ac and dc.
- Give reasons for transmitting electricity as ac.
- Draw a fully labelled diagram of a motor.
- State energy changes that occur when a motor is used to pump water.
- Distinguish between a motor and a generator in terms of energy changes.
- Describe and explain how a bicycle dynamo lights the bulb.
- Give any two electrical hazards and for each hazard give a corresponding safety precaution.
- Describe how a three-pin plug is wired.
- State three methods by which heat is transferred.
- Describe and explain why:
- In cold countries, houses are painted dull black.
- In hot countries, houses are painted white/shiny colours.
- Draw a diagram to show convection currents in water in a flask in which a crystal of potassium permanganate is gently heated.
- Define a machine.
- Give three examples of machines.
- A load of 60N is lifted by an effort of 5N over a height of 2m. Calculate:
- The mechanical advantage of the system.
- The velocity ratio and hence.
- The efficiency of the machine.
- Describe how energy is lost machines and give two ways of reducing the energy losses.
- What is pressure and what are the units of pressure.
- Name the instrument used to measure pressure in fluids.
- Name two types of pumps.
- Draw a fully labelled diagram of a named pump and describe its operation.
- What principles of liquid pressure do hydraulic systems use?
- Describe how the following simple hydraulic systems function and operate:
- A siphon used to transfer diesel from a container into the car tank.
- Car braking system.