(i)

Temperature of boiling water

100^o C or 373 K or 212^oF

(ii)

Nail 1 will fall off first followed by nail 2, 3 and 4 in that order.

(iii)

A will have the highest temperature followed by B then C and D will have the lowest temperature.

(iv)

Conduction

(v)

Effects of heat that is associated with the experiment

1. Heat transfer
2. Wax melts/water vaporizes
3. Expansion of metal/water
4. Decrease in density for metal/water
5. Water evaporates faster

(vi)

Aim of the experiment

To show that metals are good conductors of heat

OR

Heat travels through metals

(i)

To remove air/oxygen

(ii)

The oil on top of the water in set-up B is to prevent air/oxygen from dissolving back into the water.

(iii)

The purpose of the rubber stopper in set-up C is to prevent water/moisture from entering the test tube.

(iv)

The nail in set-up A rust because oxygen/air and water/moisture were present.

(v)

Aim for the experiment

To show that air/oxygen and water/moisture are necessary for rusting to take place.

(vi)

Oil or grease prevents air/oxygen and water/moisture from coming into contact with the metal for rusting to occur.

(i)

I → To kill the cells of the leaf/to stop all chemical reactions in the leaf
II → To decolorize the leaf/to remove the green pigment/chlorophyll from the leaf
III → To soften the leaf/remove or wash off alcohol from the leaf
IV → To test for the presence of starch in the leaf

(ii)

Leaf A changes from whitish/brownish to blue-black.

(iii)

Leaf A was in sunlight and therefore photosynthesis occurred but leaft B was in darkness so photosynthesis did not occur.

OR

Leaf A produced starch but leaf B did not produce starch.

(iv)

Aim for the experiment

To show that sunlight was necessary/important for photosynthesis/starch formation to occur.

(i)

Dry cell in use

Chemical energy → Electrical energy

(ii)

Solar panel in use

Light energy → Electrical energy

(iii)

Electric stove in use

Electrical energy → Heat energy

(iv)

Hammering of a piece of metal

Chemical → Potential → Kinetic → Heat/Light/Sound

OR

Chemical → Mechanical → Heat/Light/Sound

OR

Chemical → Kinetic → Heat/Light/Sound

(i)

Ways in which staking is important in vegetable production

1. It supports weak/climbing stems
2. Promotes air circulation
3. Allow for easy penetrating of sunlight
4. Helps to produce clean fruits
5. It helps protects fruits from diseases/pest
6. Cultural practices such as weeding and spraying can easily be carried out
7. It facilitates harvesting
8. It reduces/minimuzes/prevents fruits from diseases/rot
9. Improves fruit quality
10. Supports plants during strong winds

(ii)

Ways in which pruning is important in vegetable production

1. It encourages easy harvesting
2. It improves air circulation in the farm
3. It promotes light penetration
4. It checks the spread of diseases
5. It prevents the spread of pests
6. It promotes the production of bigger fruits
7. It beautifies ornamental plants
8. It aids clearing of weeds

i)

An acid is a proton donor

OR

An acid is a substance/compound that produces excess hydrogen ion (H⁺) in water.

An acid is a substance that contains replaceable hydrogen.

ii)

Differences between an acide and a base

i)

Pressure is force per unit area or the force acting (normally) per unit area

OR

Pressure = $\frac{\mathrm{(Normal)\; Force}}{\mathrm{Area}}$

ii)

Force = 200 N

Area = 50 m²

Pressure = $\frac{200}{50}$

Pressure = 4 Nm^-2 or 4 Pa

i)

Unicellular is a living organism that consists of only once cell.

ii)

Multicellular, living organisms that consist of many cells.

i)

Photosynthesis is a process whereby green plants containing chlorophyll manufacture food/carbohydrates/starch/glucose from carbon dioxide and water in the presence of sunlight.

ii)

Importance of photosynthesis to animals

1. Food/carbohydrates/starch/glucose produced provides energy for animals
2. Oxygen released is used for respiration
3. Accumulation of carbon dioxide is prevented since they are used by plants during photosynthesis

i)

To compare the rate of water drainage in different types of soil/compare the water holding capacity of types of soils.

ii)

Soil K/Sandy soil

iii)

Soil M/Clayey soil

iv)

Soil K/Sandy soil

v)

Soil M/Clayey soil

vi)

Soil L/Loamy soil

i)

I → toxic/poisonous
II → corrosive
III → flammable/inflammable
IV → no smoking/no naked flame

ii)

iii)

Places where no smoking (IV) is displayed

1. Petrol station/filling station
2. Gas station
3. Petrol tankers
4. Gas tankers
5. Public places/Any named public place e.g hospital,hotels etc.
6. Fuel storage areas

iv)

I, II and III

i)

Simple machine

ii)

A → Wheelbarrow
B → Inclined plane
C → Pulley
D → Gear

iii)

I → Effort
II → Load
III → Pivot/Fulcrum

iv)

Effort

v)

i)

I → Stomach
II → Small intestine/ileum
III → Large intestine/colon
IV → Rectum
V → Oesophagus/gullet

ii)

iii)

End-products of digestion

1. Amino acid
2. Glucose
3. Fatty acids/glycerol

(i)

In the depths of the ocean where it is always dark, there are no green plants

Light does not get to those depths and therefore photosynthesis cannot occur there.

(ii)

On an island where there are no insects and birds, the pawpaw plant produces only flowers but no fruits

Insects and birds transfer pollen grains for pollination of pawpaw flowers and in their absence fertilization does not occur and there is no fruit formation.

OR

Insects and birds are agents of pollination/transfer pollen grains. In their absence no fertilization and no fruit formation occur.

(i)

Laws of reflection

1. The incident ray, the reflected ray and the normal at the point of incidence all lie in the same plane
2. The angle of incidence is equal to the angle of reflection

(ii)

A labelled diagram to show the reflection of light on a plane mirror