(i)

Functions of the cell membrane

1. It protects a cell
2. It allows only selected substances to enter or leave the cell

(ii)

Function of the chloroplast

It contains chlorophyll (green pigment) which traps sunlight for photosynthesis

(iii)

Functions of the nucleus

1. Embodies the genetic information (genes) of the organism
2. Makes cell division or reproduction possible
3. Controls the activites of the cell

i)

Simple machine is a device that makes work easier/faster.

OR

Simple machine a device which enables a small force (effort) to overcome a large force (load).

ii)

Examples of a simple machine

1. Lever (Examples are a crowbar, claw hammer, a pair of pliers)
2. Wheel and axle (Examples are the steering wheel of a car, bicycle pedal)
3. Pulley (Examples are a pulley used in raising a load)
4. The inclined plane (Examples are ramps, staircases, hilly roads)
5. The wedge (Examples are knife, axe, plough)
6. Screw (Examples are A screw bolt)

i)

Rusting is the reaction of iron or iron containing substances with water/moisture and air/oxygen to form an oxide of iron.

ii)

Effects of rusting

1. It causes iron to lose its strength/structure resulting in accident
2. It can cause collapse of building and bridges resulting in maintenance cost
3. It causes iron to lose its lustre

i)

Food nutrients are substances which when taken in by living things help in performing of life activities

OR

Food nutrients are essential materials/substances present in food which when taken in by living things help in performing of life activities

ii)

Carbohydrate → Bread, maize
Fats and oil → Palm fruits, margarine
Protein → Beans, meat

i)

Effects of malnutrition in farm animals

1. Loss of weight/stunted growth
2. General body weakness
3. Reduced activity
4. Dullness
5. Less resistant to diseases
6. Reduced reproduction
7. Poor formation of bones

ii)

Viral diseases of farm animals

1. Rinder-pest
2. Newcastle
3. Gumboro
4. Fowl pox
5. Cow pox
6. Marek's disease
7. Swine fever
8. Bird flu
9. Foot and mouth disease

i)

Black pod

ii)

Fungus/Phytophthora

iii)

Systems of disease

1. Beads/pod becomes black
2. Brown spores/spots/patches
3. Powdery spores
4. Black patches/spots

iv)

Farm practices that promote disease

1. Leaving farm weedy/bushy
2. Excessive shading of plants
3. Planting infected seedlings/seeds
4. Poor field sanitation/hygiene
5. Use of infected tools/equipment on farm
6. Overcrowding of plants

v)

Practices to control disease

1. Remove/burn infected/infested pods
2. Weed regularly
3. Spray pods with recommended fungicide/recommended chemical
4. Remove excess shade
5. Prune (diseased) branches/Pruning

i)

a = 2.0 cm
b = 4.0 cm
c = 5.0 cm

ii)

Area = Length x Breadth

Area for face A

Area = a x b
Area = 2 cm x 4 cm = 8.0 cm²

Area for face B

Area = b x c
Area = 4 cm x 5 cm = 20.0 cm²

iii)

Pressure = $\frac{\mathrm{Force}}{\mathrm{Area}}$

Force = 100N

iv)

When area is small, pressure is high/when area is large, pressure is small

OR

Pressure and area are inversely proportional.

i)

A → Molar/premolar
B → Canine
C → Incisor

ii)

Functions of A (Molar/Premolar)

1. For grinding
2. For crushing
3. For chewing

Functions of B (Canine)

1. For stabbing
2. For tearing
3. For piercing

Functions of C (Incisor)

1. For cutting
2. For biting

iii)

Differences between A (Molar/premolar) and B(Canine)

iv)

Ways of ensuring proper dental care

1. Regular visit to the dentist
2. Regular brushing of teeth
3. Avoiding excessive intake of sugary food
4. Eating food rich in vegetables
5. Eating a lot of fruits
6. Eating food rich in calcium
7. Using the teeth for the right purpose
8. Avoid eating too hot/too cold foods

i)

I → Retort/clamp stand
II → Thermometer
III → Condenser
IV → Water/distilled water

ii)

(Simple) distillation

iii)

Functions of II (Thermometer)

Measures the temperature at which the mixture (sea water) boils/measures the temperature of water vapour above the mixture/measures the temperature within the flask.

Functions of III (Condenser)

Used to cool the vapour/condense the vapour/changes the vapour to water.

iv)

Physical processes involved in the method of separation

1. Boiling/heating
2. Vapourization/vaporization/evaporation
3. Condensation

(i)

Differences between electrical insulators and electrical conductors

(ii)

Effects of illegal electrical connections in the home

1. Overload of power supply
2. Drop in voltage of electricity
3. Leads to frequent power cuts
4. Leads to electrocution/electric shock
5. May cause fire outbreak
6. May damage electrical appliances
7. Leads to loss of revenue to government

(i)

Condensation is the change from the gas state to the liquid state.

(ii)

Freezing is the change from the liquid state to the solid state.

i)

I → Crown or Enamel
II → Dentine
III → Cement or Periodontal membrane
IV → Jaw bone or Root
V → Pulp Cavity

ii)

Functions of I (Crown or Enamel)

1. Protect teeth from harmful bacteria
2. Enables teeth withstand pressure of chewing
3. Cutting/chewing/protect dentine/protect pulp cavity

Functions of III (Cement or Periodontal membrane)

Holds tooth firmly in socket or jaw bone or supports the tooth

iii)

The part affected by tooth decay is V (Pulp Cavity)

iv)

Prevention of Tooth decay

1. Avoid using sharp-pointed objects
2. Avoid having dry mouth
3. Use water containing flourides to wash teeth/mouth
4. Avoid smoking
5. The teeth should be cleaned regularly after each meal/remove food particles from the teeth/flossing
6. Wash the mouth vigorously after each meal
7. Regular visit the dentist
8. Avoid eating too hot food
9. Avoid eating too much sugary food
10. Avoid eating too cold food

i)

The phenomenon illustrated is refraction of light

ii)

I → Normal
II → Incident ray
III → Angle of incidence
IV → Angle of refraction
V → Refracted ray

iii)

Why object appears closer to surface

Rays from the object at the bottom are bent away from the normal as they come out of the water. In a straight line, these rays appear to come from a point above the bottom

i)

I → Retort/clamp stand
II → filter paper
III → funnel

ii)

Function of II (Filter paper)

1. To filter solid or insoluble particles or residue
2. To separate the mud,solid or insoluble particles from the water
3. To prevent residue/solid/insoluble particles/mud from entering the filtrate

iii)

Name of filtrate is water

iv)

Physical properties of filtrate (Water)

1. It has a density of 1 gcm^-3 or 1000 kg m^-3
2. It boils at 100 ^oC
3. It freezes at 0 ^oC (at 1 atm)
4. It is colourless
5. It is tasteless or insipid
6. It is odourless
7. It has a high surface tension
8. It is a universal solvent
9. It is transparent
10. It has a neutral pH or pH of 7
11. It exists in three states (solid, liquid and gas)

v)

Other materials that could be used instead of filter paper

1. Cotton wool
2. Foam
3. Glass wool
4. Clean/white cloth

i)

Process likely to occur is erosion

ii)

Farming practices that could lead to the process occuring (erosion)

1. Bush burning
2. Deforestation
3. Continuous cropping
4. Crop removal
5. Excessive use of chemicals or inorganic fertilizers
6. Overgrazing
7. Cultivating or ploughing along slope

iii)

Farm practices that could control the process (erosion)

1. Planting cover crops
2. Terracing
3. Cultivating or ploughing slope or contour
4. Heavy mulching
5. Construction of drainage channels
6. Planting trees beside farm
7. Strip cropping
8. Contour bunding

iv)

Soil resources depleted

1. Soil organisms
2. Nutrients
3. Mineral matter
4. Soil particles or mineral matter
5. Growing crops
6. Air
7. Organic matter or humus

(i)

Differences between a physical change and a chemical change

(ii)

Difference between solution and suspension

A solution is a uniform/homogeneous mixture of a solute and a solvent where the solute completely disappear from sight in the solvent (liquid) whiles a suspension is a mixture of particles of an insoluble substance and a liquid whereby the particles of the substance float in the liquid. The small particles settle at the bottom of the container when it is left undisturbed.

(i)

Common salt in water → physical change

(ii)

Burning of charcoal → chemical change

(iii)

Melting of ice → physical change

(iv)

Hydrochloric acid in sodium hydroxide solution → chemical change

(i)

Parasite is any organism/living thing that lives in or on another organism/living thing called the host for its food and by so doing causes harm to the host.

(ii)

Examples of parasites and their hosts

(i)

Oxygen → O

(ii)

Chlorine → Cl

(iii)

Aluminium → Al

(iv)

Calcium → Ca

(i)

Self-pollination is the transfer of pollen grains from the anther of a flower to the stigma of the same flower or to the stigma of another flower of the same plant.

(ii)

Agents of pollination

1. Insects
2. Water/Rain
3. Animal/Man/Birds/Bats
4. Wind

(iii)

Function of the brightly coloured petals in insect pollination

They produce nectar which attracts insects to the plant.