(i)

Digestion is the breaking down of complex or insoluble food substances into simple and absorbable forms in the body of mammals.

(ii)

End products of digestion

(iii)

The enzyme present in saliva is known as ptyalin and it digests the starch in the food by breaking it down into maltose.

(i)

The heat of the sun reaches the earth by the process of radiation.

(ii)

Heat loss by an aluminium bowl placed on a table is filled with hot water

Heat is lost by conduction and convection.

(iii)

Reason why wood is used as a handle for some cooking utensils

Wood is used as a handle for cooking utensils because it is a bad/poor conductor of heat.

(i)

An alloy is a uniform/homogeneous mixture of a metal and another metal or a non-metal.

(ii)

Examples of alloys and their constituents

(i)

Balanced diet is a diet that contains all the essential food nutrients in the right proportions.

(ii)

Classes of food which should be present in a balanced diet

1. Carbohydrates
2. Proteins
3. Fats and oils
4. Vitamins

(iii)

Protein helps to build and repair the worn out tissues in the body

Carbohydrate gives the body the energy it needs

Fats and oils provide energy for the body

Vitamins protect the body from diseases

(i)

How ions are formed from atoms

1. Ions are formed when an atom gains or loses an electron
2. When an atom gains an electron, the number of electrons becomes greater than the number of protons and so a negative ion (Anion) is formed
3. When an atom loses an electron, the number of protons becomes greater than the number of electrons and so a positive ion (Cation) is formed

(ii)

Differences between a proton and an electron

(i)

The gas which is used in both rusting and burning is oxygen

(ii)

Ways in which rusting can be prevented in everyday life

1. Painting
2. Galvanizing (electroplating)
3. Greasing
4. Oiling
5. Alloying

(i)

Green grass → grasshopper → bird

OR

Green grass → goat → man

(ii)

Diseases that can be controlled by immunization

1. Tuberculosis
2. Measles
3. Poliomyelitis
4. Whooping cough
5. Diphtheria
6. Tetanus
7. Yellow fever
8. Cholera

(i)

Potential energy → Kinetic energy → Sound energy → Heat energy

(ii)

Appliances which use electromagnets in their operation

1. Telephone receivers
2. Loudspeakers
3. Electric bells
4. Burglar alarms
5. Microphones

(iii)

Ways in which a magnet can lose its magnetism

1. Heating the magnet in fire
2. Striking the magnet continuously with a hammer
3. Placing it in a solenoid through which an alternating current flows

i)

A transistor is a three terminal (a base, emitter and collector) semiconductor device.

ii)

Uses of a transistor

1. Used as an amplifier
2. Used as a switch
3. Used as a rectifier
4. Used for tuning in radios
5. Used as a voltage/current regulator

i)

Suitable solvents for grease

1. Petrol
2. Kerosene
3. Methylated spirit

ii)

Suitable solvents for ink stain

1. Milk
2. Alcohol
3. Parazone
4. Shaving cream
5. Kerosene

iii)

Suitable solvents for starch

1. Alcohol
2. Acetone

iv)

Suitable solvents for cube sugar

Water

v)

Suitable solvents for oil paint

1. Turpentine
2. Kerosene
3. Petrol
4. Thinner

vi)

Suitable solvents for iodine

1. Ethanol/Alcohol
2. Potassium iodide solution

i)

Respiratory organ is an organ used by living organisms for gaseous exchange

ii)

Structures of the respiratory system of humans

1. Trachea
2. Lungs
3. Alveolus
4. Larynx
5. Diaphragm
6. Bronchus/Bronchi
7. Nostril/Nose
8. Nasal cavity
9. Intercostals muscle
10. Ribs
11. Pharynx

i)

Agricultural chain is a series of stages that are connected in the production of agricultural goods/services.

ii)

Types of agricultural chain

1. Production
2. Processing
3. Supply
4. Value

(i)

Reasons which indicate that respiration and burning are similar processes

1. Both processes require oxygen/air to function
2. Both release energy whenever they occur
3. Both are chemical changes/involve the use of energy

(ii)

Cross-pollinationis the transfer of pollen grains from the anther of a flower to the stigma of another flower on another plant of the same species.

(iii)

Methods by which cholera can be controlled and prevented

1. Drinking of pure/boiled water
2. Burying/destroying/covering of excreta/faeces (of cholera patients)
3. Covering of food/keeping food in safes
4. Avoid eating raw vegetables or fruits which have not been washed properly
5. Eating hot foods or avoid eating cold foods
6. Washing hands after attending nature's call
7. Immunization/vaccination

(i)

Three coldest planets

1. Uranus
2. Neptune
3. Pluto

(ii)

The planets are cold because they are far away from the sun.

(iii)

Density = $\frac{\mathrm{Mass}}{\mathrm{Volume}}$

Mass = 150 g
Volume = 250 cm³

Density = $\frac{\mathrm{150\; g}}{250{\mathrm{cm}}^3}$

Density = 0.6 gcm^-3

(i)

Suitable solvents for grease

1. Kerosene
2. Petrol

(ii)

Suitable solvents for oil paint

1. Kerosene
2. Turpentine
3. Petrol

(iii)

Suitable solvent for alcohol

Water

(iv)

Suitable solvent for sugar

Water

i)

Potential Energy

ii)

Potential Energy = Mass x Acceleration due to gravity (g) x Height

P.E = m x g x h = mgh

Mass = 100 kg, g = 10 ms^-2, height = 2 m

Potential Energy = 100 x 10 x 2 = 2000 J

i)

Matter is anything that has mass/weight and can occupy space.

ii)

States of matter

1. Solid
2. Liquid
3. Gas
4. Plasma

i)

Nature of loamy Soil

Contains roughly equal quantities of sand, silt and clay and large amount of humus/organic matter or nutrient

ii)

Plant Nutrients

1. Nitrogen
2. Phosphorus
3. Potassium
4. Calcium
5. Magnesium
6. Sulphur
7. Zinc
8. Iron
9. Copper
10. Boron
11. Manganese
12. Molybdenum

i)

Causative organism for cholera & Tubercolosis

ii)

Prevention of cholera

1. Washing of hands under running water with soap before eating or after visiting the toilet
2. Boiling of water before drinking/ Drinking treated water
3. Proper disposal of faeces
4. Eating food hot
5. Keeping the environment clean