i)

Air pollution is the release of toxic/poisonous substances into the atmosphere.

ii)

Humans activities that lead to air pollution

1. Discharge of gases from factories
2. Smoke from exhaust engines and other machines
3. Smoke from domestic fires
4. Discharge of chloroflourocarbons from aerosol sprays and some refrigerators
5. Bush burning
6. Dust from open cast mining
7. Dust from sand winning and stone quarrying
8. Dust from construction
9. Smoke from cigarette/smoking

i)

Modes of heat transfer

1. Conduction
2. Convection
3. Radiation

ii)

Medium for mode of heat transfer

1. Conduction → Solid
2. Convection → Liquid/gas/fluid
3. Radiation → vacuum/no material medium

(i)

Negative charged particles

1. Anion/negative ion
2. Electron
3. Beta particle

(ii)

Positive charged particles

1. Cation/positive ion
2. Proton
3. Alpha particle

(iii)

Particles with no charge

1. Atom
2. Neutron
3. Molecule

(i)

Work input = Effort x Effort distance

Work input = 25 N x 4 m = 100 J

(ii)

Work output = Load x Load distance

Work output = 20 N x 2 m = 40 J

(iii)

Efficiency of the machine = $\frac{\mathrm{Work\; out}}{\mathrm{Work\; input}}$ x 100%

Efficiency of the machine = $\frac{\mathrm{40\; J}}{\mathrm{100\; J}}$ x 100% = 40%

OR

Efficiency of the machine = $\frac{\mathrm{Mechanical\; Advantage\; (M.A)}}{\mathrm{Velocity\; Ratio\; (V.R)}}$ x 100%

Mechanical Advantage = $\frac{\mathrm{Load}}{\mathrm{Effort}}$ = $\frac{20}{25}$ = $\frac{4}{5}$

Velocity Ratio = $\frac{\mathrm{Effort\; Distance}}{\mathrm{Load\; Distance}}$ = $\frac{4}{2}$

Efficiency of the machine = $\frac{\frac{4}{5}}{\frac{4}{2}}$ x 100%

Efficiency of the machine = $\frac{4}{5}$ ÷ $\frac{4}{2}$ x 100%

Reciprocate the fraction after the ÷ and change the ÷ to multiplication (x)

Note: reciprocate means the numerator becomes the denominator and the denominator becomes the numerator.

Efficiency of the machine = $\frac{4}{5}$ x $\frac{2}{4}$ x 100%

Efficiency of the machine = $\frac{\mathrm{4\; x\; 2}}{\mathrm{5\; x\; 4}}$x 100%

Note: the 4s cancel each other.

Efficiency of the machine = $\frac{2}{5}$x 100%

Note: 5 divides itself 1 time and 100, 20 times.

Efficiency of the machine = 2 x 20% = 40%

i)

Uses of water in agriculture

1. Cleaning
2. Irrigation
3. Fishing/Fish farming
4. For fertilizer application
5. For pest control
6. Drinking/consumption by farm animals

ii)

Deep rooted crops

1. Tomato
2. Carrots
3. Yam
4. Cassava
5. Watermelon
6. Cocoyam
7. Pumpkin

i)

Circulatory system is a collection of tissues and organs which transports materials or food or water or oxygen throughout the (whole) body

ii)

i)

Mass is the amount of substance (matter) in a body or particle

Is a measure of how much matter is in an object

ii)

Density = Mass / Volume

Mass = Density x Volume

Density = 2.0 g cm^-3, Length = 3 cm

Length of a cuboid (Equal size) = Length x Length x Length

Volume of the box = 3 cm x 3 cm x 3 cm = 27.0 cm³

Mass = 2.0 g cm^-3 x 27.0 cm³ = 54.0 g

i)

ash → solid

ii)

carbon dioxide → gas

(i)

I = beaker
II = residue/particles/cotton wool/mixture/filter paper
III = filtrate

(ii)

Methods of Separation

(iii)

Class of mixtures

1. Solid - liquid mixture
2. Liquid - solid mixture

(iv)

Reason for the class of mixture

Because there is residue on the filter paper and filtrate in the beaker

(v)

possible component of the mixture in set-up B

- iron fillings/any magnetic substance
- powdered sulphur
- sand
- powdered chalk
- powdered charcoal
- any non-magenetic substance

(vi)

Function of part labelled IV (Retort/Clamp Stand)

It holds the funnel in place/holds the clamp

(i)

The system illustrated is respiratory system

(ii)

Name of the parts labelled

I = Larynx/Voice Box
II = Trachea/windpipe
III = Bronchus
IV = lung

(iii)

Role of the part labelled I (Larynx)

1. Allows air to pass through it/breathing
2. Prevent food and drink from blocking the airways
3. Produces sound/phonation

(iv)

Diseases of the respiratory system

1. Tuberculosis/T.B.
2. Bronchitis
3. Pneumonia
4. Whooping cough
5. Lung cancer
6. Influenza
7. Asthma
8. Bronchiectasis
9. Idiopathic pulmonary fibrosis/pulmonary disease
10. Common cold
11. Covid-19

(i)

Rain gauge

(ii)

Name of the parts labelled

I = funnel
II = measuring cylinder
III = rain water/water

(iii)

Use of the parts labelled I (funnel) and II (measuring cylinder)

I - directs rain water into the measuring cylinder

II - use to measure the amount/volume of rain water/collect rain water

(iv)

Ecological factor measured

Rainfall/amount of rainfall/rain

(v)

Importance of ecological factor measured

1. Protects plants roots from injury
2. Causes erosion
3. Causes leaching
4. Needed for seed germination
5. Promotes activities of soil organisms
6. Aids in easy tillage of soil
7. An agent of weathering of rocks in the soil
8. Dissolves plant nutrients for easy absorption
9. Makes soil fertile
10. Determine the type of crop to grow
11. Used for photosynthesis

(vi)

Handfork

(vii)

Use to loosen hard soil surface after heavy rainfall

(i)

Name of the components labelled

I = cell
II = switch/key
III = lamp/bulb

(ii)

Type of arrangement of resistors (R) in B is parallel

(iii)

A - makes III/bulb dim
B - makes III/bulb bright

(iv)

Reasons

A - the resistors in series have an increased resistance

B - the resistors in parallel have decreas resistance hence keep the bulb bright

(i)

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

(ii)

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

(i)

Balanced equation for the reaction

NaOH + HCl → NaCl + H₂O

(ii)

Neutralization reaction

(i)

Debeaking is the partial removal/trimming of the beak of poultry/domestic bird.

(ii)

Reasons why debeaking in poultry birds is important

1. To prevent vent pecking
2. To check feather pecking/plucking
3. To reduce wastage of feed
4. To check egg eating
5. To check cannibalism

(i)

Surface tension

(ii)

Substances to reduce surface tension

1. Kerosene
2. Oil
3. Soap/detergent
4. Diesel
5. Petrol

(i)

Why gold is preferred to iron in the making of jewelleries

Gold does not corrode/rust/react with water and oxygen/air/moisture and therefore maintains/keeps its nature/colour/lustre

(ii)

Ways of preventing rusting

1. Greasing/oiling/lubricating
2. Painting
3. Electroplating
4. Galvanizing
5. Alloying
6. Tin plating
7. Plastic coating
8. Sacrificial protection/cathodic protection