i)

Functions of leaves to the plant

1. They manufacture food for the plant
2. They help in getting rid of excess water in a plant
3. The exchange of gases between the atmosphere and a plant takes place through the stomata on the leaves

ii)

Functions of roots to the plant

1. They anchor/hold/support the plants firmly in the soil
2. They absorb water and dissolved mineral salts from the soil
3. They store excess food in some plants
4. They are responsible for exchange of gases in some plants in marshy habitats
5. In some plants, the roots are a means of reproduction

i)

eating → voluntary

ii)

walking → voluntary

iii)

sneezing → involuntary

iv)

laughing → voluntary

i)

Differences between a physical change and a chemical change

ii)

Chemical equation for the preparation of carbon dioxide

2HCl + CaCO₃ → CaCl₂ + H₂O + CO₂

i)

A machine is a device that helps us to do work easier/faster.

OR

A machine is a device that enables a small force (effort) to overcome a large force (load).

ii)

Efficiency of a machine = $\frac{\mathrm{Work\; output}}{\mathrm{Work\; input}}$

OR

Efficiency of a machine = $\frac{\mathrm{Output\; energy}}{\mathrm{Input\; enery}}$

OR

Efficiency of a machine = $\frac{\mathrm{Mechanical\; Advantage\; (M.A)}}{\mathrm{Velocity\; Ratio\; (V.R)}}$

i)

Female sexual characteristics of a human being

1. Vagina
2. Ovaries
3. Womb/uterus
4. Fallopian tubes
5. Cervix
6. Vulva
7. Breast

ii)

Sense organs in mammals

1. Eyes
2. Ears
3. Nose
4. Tongue
5. Skin

iii)

Function of the sense organs

1. Eyes → for sight
2. Ears → for hearing
3. Nose → for smelling
4. Tongue → for tasting
5. Skin → for feeling and excreting sweat

i)

A compound is the substance formed as a result of the chemical combination of two or more elements.

OR

A compound is a substance which is made up of two or more elements chemically combined.

ii)

A mixture is what is formed when two or more substances are combined physically

OR

A mixture is the substance formed as a result of the physical combination of two or more substances which can be separated by physical means.

i)

An orange falls from a tree to the ground

Potential energy → Kinetic energy → Sound energy + Heat energy

ii)

A carpenter hits a nail with a raised hammer

Potential energy → Kinetic energy → Sound energy + Heat energy

i)

Human activities that can cause an increase in soil erosion

1. Road construction
2. Bush fires
3. Deforestation
4. Farming/over-cropping
5. Sand wining/soil removal for building and road construction
6. Over-grazing by farm animals

ii)

Ways of preventing soil erosion in agriculture

1. Ploughing across slopes/Contour ploughing
2. Growing of cover crops
3. Practicing crop rotation
4. Afforestation and reafforestation
5. Bush fallowing/land rotation
6. Erecting windbreaks
7. Terracing
8. Strip cropping
9. Mulching

i)

Work is said to be done when an application of a force moves an object through a distance in the direction of the force

OR

Work is said to be done when a force moves a body through a distance in the direction of the force.

ii)

The unit of work is joules

i)

Heat is the energy which causes rise in temperature of bodies while temperature is the degree of hotness or coldness of a body.

ii)

The unit of heat is joules and temperature is kelvin or degree celsius

i)

ii)

Angle of incidence = Angle of reflection

Angle of incidence = 90° - 55° = 35°

∴ Angle of reflection = 35°

i)

MgCl₂ → Magnesium chloride

ii)

FeS → Iron (II) sulphide

iii)

NH₄OH → Ammonium hydroxide

iv)

AgCl → Silver chloride