i)

Food chain is the linear relationship between organisms that shows the transfer of energy from one organism to another through feeding and being fed on by another.

ii)

Because plants produce/make their own food through the process of photosynthesis

iii)

Consumer(s)

i)

Name of shadows

ii)

It illustrates that light travels in a straight light

i)

Mixture is what is formed when two or more substances are put together/combine physically.

ii)

Why some mixtures are thoroughly stirred before they are used

Mixtures are thoroughly stirred to make a homegenous/uniform mixture

OR

Mixtures are thoroughly stirred to make even/uniform concentration

i)

Reflection of light is the bouncing of light from a surface.

ii)

Characteristics of the images formed by plane mirrors

1. It is erect (upright)
2. It is virtual
3. It is laterally inverted
4. Same distance behind mirror as object is in front of mirror
5. Same size and shape as the object

i)

Fertilizer is any substance which is applied to the soil or plant to supply nutrients for plant growth.

ii)

Examples of an inorganic fertilizer

1. Urea
2. Muriate of potash
3. Single super phosphate (SSP)/sulphate of ammonia
4. NPK

i)

Indiscriminate sex is the act of having sexual intercourse with different/many/multiple partners.

ii)

Dangers of indiscriminate sex on humans

1. Acquiring sexually transmitted diseases
2. Unwanted pregnancy/becoming pregnant
3. Causing abortion

(i)

Neutralization reaction is a chemical reaction between an acid and a base to form salt and water only.

(ii)

(i)

Milky Way is the galaxy in which the solar system is located.

OR

Milky Way is the group of planets and stars which the earth belongs to.

(ii)

Uses of artificial satellites

1. For space exploration
2. For communication/broadcasting/telephone call
3. For weather forecasting/collecting information on the weather
4. For scientific research/experimental research/internet
5. For military purposes/spying/espionage
6. To study the universe
7. For map making
8. For navigation/satellite for navigation

(i)

Habitat is a natural living place of an organism.

OR

Habitat is a place where an organism spends parts/all of its life.

(ii)

Examples of a habitat

1. Aquatic e.g Ponds, streams, lakes, rivers, marine (sea)

2. Terrestrial e.g Forest, Savannah, thicket

3. Arboreal e.g Tree branches, leaves

(i)

Function of labelled parts

I → Carries blood from the heart/left ventricle to the circulatory system
II → Brings (oxygenated) blood from lungs to heart/left auricle/atrium
IX → Brings (deoxygenated) blood from the body to heart/right atrium/right side of heart
X → Carry (oxygen deficient) blood from heart to lungs/right side of heart/right ventricle to lungs

(ii)

Why the left lower part of the heart has a thicker muscle

Contracts to pump (oxygenated) blood with high pressure to all parts of the body

OR

To generate high pressure to allow blood to reach all parts of the body

(iii)

Ways by which the flow of blood to and from the mammalian heart can be kept at acceptable levels

1. Exercising
2. Not smoking
3. Taking iron rich foods/balanced diet
4. Regulating one's blood pressure
5. Stress management
6. Get enough sleep
7. Healthy weight
8. Limit alcohol consumption
9. Manage diabetes
10. Regular health check-up

(iv)

Parts of the heart where oxygenated blood can be found

1. Aorta
2. Pulmonary vein
3. Left atrium
4. Left ventricle

(i)

How P (Maize grains) is planted on seedbed

1. Make holes (using cutlas or stick/dibber)
2. Place 2 or 3 seeds per hole and cover with soil

How Q (Tomato seedlings) is planted on seedbed

1. Remove a plant seedling from a nursery gently
2. Place the seedling in a prepared hole
3. Firm the soil around the seedling with hands
4. Water immediately

How R (Cassava cuttings) is planted on seedbed

1. Dig a hole/loosen the soil/dig trenches
2. Turn the cutting with the nodes/buds facing upwards
3. Place (two thrifts of) cutting into the hole
4. Firm soil around the cutting

(ii)

Conditions under which R(Cassava cuttings) can be cultivated to produce high yield

1. Adequate rainfall/water/irrigation
2. Fertile soil
3. Soil with good structure
4. Absence of diseases
5. Absence of pests
6. Sunlight

(i)

Function of labelled parts

I → Converts chemical energy to electrical energy/generates voltage
II → Closes and opens circuit/allows charges to flow or not flow
III → Stores electric charges
IV → Opposes flow of charges/current

(ii)

V = IR

R = $\frac{\mathrm{V}}{\mathrm{I}}$

Voltage (V) = 2.4 V

Current (I) = 0.8 A

Resistance (R) = $\frac{\mathrm{2.4\; V}}{\mathrm{0.8\; A}}$ = 3 Ω

Note: Mark is deducted for answer without a unit (Ω)

(iii)

Way of conserving the value of the part labelled I (Cell/Battery) in the circuit

Open key/switch when not taking readings.

(iv)

Observations that can be made when the circuit is closed

1. Ammeter will read/deflect
2. Voltmeter will read/deflect

(i)

Description of the process of the experiment

1. Make the set-up as shown in the diagram
2. Put two immiscible liquids into the separating funnel/I
3. Allow the mixture to stand
4. And separate into two layers
5. Open the tap to drain the liquid at the bottom into the conical flask/III
6. Close the tap after draining the liquid at the bottom

Note: the steps must be in sequence. When sequence is broken, marking is stopped.

(ii)

Function of the labelled parts

II → Regulate/control of the flow of liquid
IV → To hold the separating funnel

(iii)

Precautions that should be taken to obtain reliable results when performing this experiment

1. The tap should be opened gently to release only the bottom liquid
2. The retort stand should be firm enough to hold the separating funnel
3. The mixture should be left to stand for sometime to settle and separate
4. The retort stand should be placed on a flat surface

i)

H₂O → Water/dihydrogen monoxide/hydrogen oxide

ii)

MgO → Magnesium oxide

iii)

CaCO → Calcium oxide

iv)

CaCl₂ → Calcium chloride

i)

Length of a rope → Metre rule/tape measure/ruler/surveyor's tape

ii)

Mass of a stone → Beam balance/chemical balance/top pan balance/electronic balance

iii)

Temperature of a liquid → Thermometer

iv)

Volume of a liquid → Volumetric flask/pipette/graduated cylinder/measuring cylinder/burette/graduated beaker

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