(i)

Diffusion is the process whereby molecules/particles of a liquid/gas move from a region of higher concentration to a region of a lower concentration until they are uniformly spread throughout an occupied space.

(ii)

Surface tension is the property of a liquid which makes the surface behave as if it were stretched elastic skin.

(iii)

Capillarity is the rise or fall of liquids in small/narrow tubes/columns as a result of adhesion and surface tension forces.

(i)

Composition of blood

1. Serum/plasma
2. Red blood cells
3. White blood cells
4. Platelets

(ii)

Functions of blood

1. It transports oxygen from the lungs to the tissues
2. It transports/distributes/carries digested food substances to the tissues
3. It transports excretory materials/it carries carbon dioxide (CO₂) or nitrogenous waste from the tissues to the lungs
4. It protects the body against diseases/produces antibodies
5. It forms clot to prevent loss of blood/excessive bleeding
6. It transports hormones
7. It regulates body temperature
8. It maintains the turgidity of cells in the body
9. It prevents entry of germs into the body through a wound

(i)

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

(iii)

Chemical symbols

(i)

Defects of the eye

1. Long sightedness/Hypermetropia
2. Short sightedness/Myopia
3. Astigmatism/Presbyopia

(ii)

Correction of defects

Long sightedness/Hypermetropia

Wearing converging/convex lens

Short sightedness/Myopia

Wearing diverging/concave lens

Astigmatism/Presbyopia

Medical treatment/use of special lenses

(i)

A satellite is an object which moves around a planet in space

(ii)

Differences between a natural and an artificial satellite

(iii)

Uses of artificial satellites

1. For exploring the planets/moons
2. For scientific research/experimental research/internet
3. To study the universe
4. For communications/broadcasting/telephone call
5. For weather forecast/collecting information on the weather
6. Map making
7. Spying
8. For navigation/satellite for navigation
9. Military purposes

(i)

Reaction: NH₃ + HCl → NH₄Cl

New substances formed: Ammonium chloride (NH₄Cl)

(ii)

Reaction: NaOH + HCl → NaCl + H₂O

New substances formed: Sodium chloride (NaCl) and water (H₂O)

(iii)

Reaction: CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O

New substances formed: Calcium chloride (CaCl₂), carbon dioxide/Carbon (IV) oxide (CO₂) and water (H₂O)

(i)

A machine is a device that makes work easier or faster

OR

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

(ii)

Mechanical advantage of a machine is the ratio of the load to the effort needed to raise the load

OR

Mechanical advantage (M.A) = $\frac{\mathrm{Load\; (L)}}{\mathrm{Effort\; (E)}}$

(iii)

Velocity ratio of a machine is the ratio of the distance moved by the effort to the distance moved by the load

OR

Velocity ratio (V.R) = $\frac{\mathrm{Distance\; moved\; by\; effort}}{\mathrm{Distance\; moved\; by\; load}}$

(i)

General causes of diseases

1. Consequences of malnutrition
2. Vitamin or mineral salts deficiency
3. Air or water pollution
4. Chemical/food poisoning
5. Defects resulting from injuries
6. Poor sanitation
7. Poor personal hygiene
8. Not covering food properly
9. Pouring faeces or going to nature's call around
10. Throwing empty tins/cans about
11. Drinking bad/untreated water

(ii)

Ways by which diseases can be prevented

1. Washing hands before eating
2. Washing hands with soap after visiting toilet
3. Observing personal hygiene
4. Proper disposal of refuse/sewage
5. Keeping the environment clean
6. Drinking safe/treated water
7. Vaccination/immunization against diseases
8. Exercising the body

(i)

cassava → stem cutting

(ii)

onion → bulb

(iii)

banana → sucker

(iv)

yam → stem tuber

(v)

ginger → rhizome

(vi)

pineapple → sucker/crown/slips

(i)

Density is the mass per unit volume of a substance

OR

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

(ii)

How yto determine the density of a sample of soil

Method I

1. The mass of an empty wooden rectangular box is measured by means of a beam balance and the result is recorded as M₁ g
2. The rectangular box is filled to the brim with the sample of soil
3. The mass of the box containing the sample of soil is measured by means of a beam balance and the result is recorded as M₂ g
4. The length, breadth and height of the box is measured

Calculations

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

Mass of soil sample = (M₂ - M₁) g

The volume of the box equals to the volume of the soil sample since the box is filled to the brim with the soil

Volume of soil sample = Length x Breadth x Height of box = V cm³

Density of soil = $\frac{{\mathrm{M}}_2-{\mathrm{M}}_1}{\mathrm{V}}$ g/cm³

Method II

1. The mass of the soil sample is measured by means of a beam balance and the result recorded as M g

2. Water is poured into a measuring cylinder to a suitable level/about half full and the initial level of water recorded as V₁ cm³

3. The soil sample is gently poured into the measuring cylinder containing the water
4. The level of the water goes up and this new level of water is recorded as V₂ cm³

Calculations

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

Mass of soil sample = M g

Volume of soil sample = (V₂ - V₁)cm³

Density of soil = $\frac{\mathrm{M}}{{\mathrm{V}}_2-{\mathrm{V}}_1}$ g/cm³

(i)

Common salt → Water

(ii)

Paint → Kerosene/turpentine/petrol

(iii)

Coal tar → Kerosene/turpentine/petrol

(iv)

Sucrose → Water

Note: sucrose is a sugar

(v)

Chlorophyll → Alcohol/organic solvent