(i)

A → Fats and Oils/Lipids
B → Protein
C → Reducing Sugar/Glucose
D → Starch

$\frac{1}{2}$ mark each x 4 = 2 marks

(ii)

Colour Formed For A (Fats and Oils/Lipids)

Red-stained oil layer

Colour Formed For B (Protein)

Colour change from pale blue to lilac/violet/purple

Colour Formed For C (Reducing Sugar/Glucose)

Colour change from blue to green/yellow/orange/brick red

Colour Formed For D (Starch)

Color change from yellow-brown to blue-black/purple

$\frac{1}{2}$ mark each x 4 = 2 marks

(iii)

Part(s) of the digestive system where the food substances A, B and D are digested

A (Fats and Oils/Lipids) → Small Intestine (1 mark)
B (Protein) → Stomach ($\frac{1}{2}$ mark) and Small Intestine ($\frac{1}{2}$ mark)
D (Starch) → Mouth ($\frac{1}{2}$ mark) and Small Intestine ($\frac{1}{2}$ mark)

Total marks = 3 marks

(iv)

End product of digestion for food substances A, B and D

A (Fats and Oils/Lipids) → Fatty acids and glycerol ($\frac{1}{2}$ mark)
B (Protein) → Amino acids ($\frac{1}{2}$ mark)
D (Starch) → Glucose ($\frac{1}{2}$ mark)

Total marks = 1.5 marks

(v)

Functions of food substances A (Fats and Oils/Lipids)

1. Energy Source & Storage: A concentrated source of energy, storing more calories per gram than carbs or protein.

2. Essential Fatty Acids: Provide linoleic and alpha-linolenic acids, necessary for body functions but not produced internally.

3. Vitamin Absorption: Necessary for absorbing vitamins A, D, E, and K.

4. Structural Components: Form cell membranes and are vital for brain health and nerve function.

5. Protection & Insulation: Subcutaneous fat insulates against cold, while visceral fat cushions vital organs like the heart and kidneys.

6. Hormone Production: Involved in producing and regulating hormones, like leptin for appetite signaling.

Any 1 x $\frac{1}{2}$ mark = 0.5 mark

Functions of food substances B (Protein)

1. Enzymes: Speed up (catalyze) chemical reactions, like breaking down food for energy.

2. Structure: Provide frameworks for cells, tissues (collagen in skin/bones), muscles, hair, and nails.

3. Transport & Storage: Carry molecules like oxygen (hemoglobin) and store essential nutrients (iron, calcium).

4. Immunity: Form antibodies to fight off invaders like bacteria and viruses.

5. Signaling: Act as hormones and receptors, sending messages between cells (e.g., insulin).

6. Movement: Enable muscle contraction (actin, myosin).

7. Fluid & pH Balance: Help maintain the right balance of fluids and acidity in the body.

8. Energy: Can be used as an energy source if Carbohydrates and fats and oils are insufficient.

Any 1 x $\frac{1}{2}$ mark = 0.5 mark

Functions of food substances D (Starch)

1. Energy Production: Digested into glucose, which cells convert to ATP (adenosine triphosphate) for immediate energy to power bodily functions.

2. Energy Storage: Excess glucose is stored as glycogen in the liver and muscles for later use, maintaining blood sugar levels.

3. Building Macromolecules: Used as building blocks for vital molecules like DNA, RNA, and ATP.

4. Protein Sparing: Ensures protein is used for building tissues rather than being broken down for energy, preventing muscle loss.

5. Lipid Metabolism: Helps in the breakdown of fats, preventing the buildup of ketones (ketosis).

6. Digestive Health (Fiber): Fiber, a complex Carbohydrates, adds bulk to stool, promotes regularity, and supports a healthy gut.

Any 1 x $\frac{1}{2}$ mark = 0.5 mark

Total marks = 1.5 marks

(i)

A → Sickle
B → Prunning saw
C → Hoe
D → Rake
E → Garden/hand trowel

$\frac{1}{2}$ mark each x 5 = 2.5 marks

(ii)

Uses of A (Sickle)

1. For harvesting fruits/cereals e.g. rice in the field
2. For light weeding
3. For cutting pasture grasses

Uses of B (Prunning saw)

1. For prunning excessive branches of trees
2. For cutting of budded seedings
3. For cutting wood/log

Uses of C (Hoe)

1. For making ridges and mounds
2. For planting crops and transplanting
3. For weeding
4. For harvesting tuber crops
5. For light digging

Uses of D (Rake)

1. For leveling the soil
2. For removing stones and rubbish from seed bed
3. For covering seeds with soil
4. For spreading manure on seed beds
5. For breaking large soil lumps into fine particles
6. For spreading/turning farm produce e.g. seeds, grains during drying

Uses of E (Garden/hand trowel)

1. For digging small holes for planting seedlings
2. For transplanting seedlings
3. For light weedings in flower beds

$\frac{1}{2}$ mark each x 5 = 2.5 marks

(iii)

Ways of maintaining the farm tools

1. Clean the tools aftter use/wash and dry after use
2. Rub the metal blades with oil to prevent rusting
3. Sharpen the metal blades regularly
4. Keep the farm tools in a cool dry place
5. Keep wooden handles away from termites
6. Replace broken parts

Any 3 x 1 mark = 3 marks

(iv)

Farm tools that could be used in place of B (Prunning saw)

1. Secateur
2. Shears
3. Cutlass/matchet

Any 1 x 2 marks = 2 marks

(i)

The solar system ($\frac{1}{2}$ mark)

(ii)

I → Mercury
II → Venus
III → Earth
IV → Mars
V → Jupiter
VI → Saturn
VII → Uranus
VIII → Neptune

$\frac{1}{2}$ mark each x 8 = 4 marks

(iii)

II/Venus Which part is the hottest ($\frac{1}{2}$ mark)

Note: Venus is the hottest planet due to its thick, heat-trapping atmosphere

(iv)

IV/Mars is known as the "Red" planet" ($\frac{1}{2}$ mark)

(v)

VI/Saturn is known for its prominent rings ($\frac{1}{2}$ mark)

(vi)

Terrestrial (rocky) planets

I/Mercury
II/Venus
III/Earth
IV/Mars

$\frac{1}{4}$ mark each x 4 = 1 mark

Note: the first four planets are terrestrial (rocky) planets

(vii)

Characteristics of III (Earth)

1. It is spherical or geoid shaped
2. It has more oxygen than other planets

3. It is the only planet which supports life

4. It has one natural satellite
5. It is the 5th largest planet
6. It rotates on its axis
7. It rotates eastwards (from west to east)
8. It revolves round the sun
9. It completes a rotation in 24 hours
10. It completes a revolution in 365 1/4 days
11. It has different seasons
12. It is the third planet from the sun
13. The surface is made up of 29% land and 71% water
14. It is about 148.8 million km away from the sun
15. It has outer solid crust
16. It possesses an inner molten core
17. It surrounded by gaseous envelope
18. It the zone of life on the earth is at the interface of hydrosphere, lithosphere and the atmosphere
19. It axis is inclined at angle of 66½°
20. It has surface area of 443 million km²
21. It has equatorial circumference of 40,085 km
22. It has polar circumference of 39,955 km
23. It has equatorial diameter of 12,762 km
24. It is the most dense planet
25. It has polar diameter of 12,722km

Any 3 x 1 mark = 3 marks

(i)

Pond/fresh water (1 mark)

(ii)

Trophic level of labelled parts

I → Producer/first/1
II → Primary consumer/second/2
III → Secondary consumer/tertiary/3
IV → Tertiary consumer/quatemary/4

$\frac{1}{4}$ mark each x 4 = 1 mark

(iii)

Food chain

I/plants → II/tadpole → III/small fish → IV/big fish

$\frac{1}{2}$ mark each x 4 = 2 marks

Note: arrow must be shown to award mark.

(iv)

Role of the sun in the habitat

1. The sun is a source of solar/light energy
2. For plants to use to manufacture food/photosynthesis
3. Promotes the growth of plants
4. Keeps the water warm/increase in temperature

Any 1 x 1 mark = 1 mark

(v)

Effect of the absence of I/plant in the habitat

1. If they are absent, the solar/light energy is not fully utilized/captured
2. Food is not manufactured/ produced for the animal
3. Oxygen is not released into the water
4. Therefore life cannot be sustained
5. Animals find it difficult to breathe
6. Carbon dioxide accumulates
7. The environment becomes polluted
8. Eventually all the organisms die

Any 1 x 1 mark = 1 mark

(vi)

(vii)

Mode of nutrition of labelled parts

I → Autotrophic/photosynthetic
II → Herbivorous/heterotrophic
III → Carnivorous/heterotrophic
IV → Carnivorous/heterotrophic

$\frac{1}{4}$ mark each x 4 = 1 mark

(viii)

Adaptive feature of the organisms labelled I (Plant)

1. Well-developed numerous fibrous root system; for anchorage into mud
2. Long petiole; raises the leaves above water; for photosynthesis
3. Numerous root hairs; for absorption of nutrients
4. Air spaces/spongy tissues; for buoyancy/floating
5. Broad leaves; enhances absorption of sunlight for photosynthesis
6. Presence of chlorophyll/chloroplast for photosynthesis.

Any 1 x 1 mark = 1 mark

(i)

Differences between the properties of solids and gases

$\frac{1}{2}$ mark each x 2 = 1 mark

(ii)

X → Freezing
Y → Sublimation
Z → Condensation

$\frac{1}{2}$ mark each x 3 = 1.5 marks

(iii)

Properties of liquids

1. Liquids have a definite volume but no definite shape.
2. The particles in liquids are closely packed but can move/slide past each other.
3. Liquids are nearly incompressible.
4. Liquids have a moderate density compared to solids and gases.
5. Liquids can flow and take the shape of their container.

$\frac{1}{2}$ mark each x 2 = 1 mark

(iv)

Ways of conserving water in the home

1. Turn off tap intermittently while brushing teeth so as to have the water running only when washing
2. Fix leaks/leakages in pipe line/performing routine maintenance
3. Re-use of waste water for flushing toilet/watering plants where possible
4. Avoid using treated water for car washing
5. Flush toilet only when necessary
6. Lawn should be made of succulent/other plants that thrive under drought
7. Use of water-saving devices/appliances
8. Collect rain water for domestic use
9. Use bucket instead of hose pipe for washing vehicles/floors
10. Take short showers instead of baths
11. Use broom instead of hose to clean driveways/sidewalks
12. Water plants during early morning or late evening to reduce evaporation
13. Use mulch around plants to retain soil moisture
14. Avoid over-watering plants/lawns
15. Use drip irrigation for watering plants

$\frac{1}{2}$ mark each x 3 = 1.5 marks

(i)

Example of metals

1. Lithium (Li)
2. Beryllium (Be)
3. Sodium (Na)
4. Magnesium (Mg)
5. Aluminium (Al)
6. Potassium (K)
7. Calcium (Ca)

Any 2 x $\frac{1}{2}$ mark each = 1 mark

(ii)

Example of non-metals

1. Hydrogen (H)
2. Boron (B)
3. Carbon (C)
4. Nitrogen (N)
5. Oxygen (O)
6. Fluorine (F)
7. Silicon (Si)
8. Phosphorus (P)
9. Sulfur (S)
10. Chlorine (Cl)

Any 2 x $\frac{1}{2}$ mark each = 1 mark

(iii)

Example of noble gases

1. Helium (He)
2. Neon (Ne)
3. Argon (Ar)

Any 2 x $\frac{1}{2}$ mark each = 1 mark

(i)

A cell is the basic/smallest structural/building block and functional unit of life. (2 marks)

(ii)

Scientists that are associated with the discovery of the cell

1. Robert Hooke (1665) - Discovered the cell in cork.
2. Antonie van Leeuwenhoek (1674) - First observed living cells.
3. Matthias Schleiden (1838) - Proposed that all plants are made of cells.
4. Theodor Schwann (1839) - Proposed that all animals are made of cells.
5. Rudolf Virchow (1855) - Stated that all cells arise from pre-existing cells.
6. Felix Dujardin (1835) - Studied animal cells and identified the cytoplasm.

Any named scientist x 2 marks = 2 marks

(iii)

Differences between plant and animal cells

Any 2 x 1 mark = 2 marks

(i)

Work is said to be done when an application of a force moves an object through a distance in the direction of the force.

OR

Work is said to be done when a force moves a body through a distance in the direction of the force.

Note: work is zero (0) if there is no distance moved.

Any 1 x 2 marks = 2 marks

(ii)

Work done = Force × Distance

Force = 15 N
Distance = 1.2 m

Work done = 15 N × 1.2 m = 18 J

(i)

Modes of heat transfer

1. Conduction
2. Convection
3. Radiation

$\frac{1}{2}$ mark each x 3 = 1.5 marks

(ii)

Medium for mode of heat transfer

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

$\frac{1}{2}$ mark each x 3 = 1.5 marks

(iii)

Effects of heat on a substance

1. Change of state/melts/vapourises
2. Expansion/contraction/change in shape
3. Increasing temperature/decreasing temperature
4. Increase in pressure

Any 2 x 1 mark = 2 marks

(i)

Electronic configuration for X = 1

Electronic configuration for Y = 2,8,7

$\frac{1}{2}$ mark each x 2 = 1 mark

(ii)

Number of protons, electrons and neutrons of X

Atomic number = 1

Note:Atomic number is the subscript (number at the down)

Atomic number = Number of protons = 1

In a neutral atom (atom with no charge), number of protons = number of electrons

Number of electrons = 1

Mass number = Number of Protons + Number of neutrons

Mass number = 2

Note:Mass number is the superscript (number at the top)

2 = 1 + neutrons

neutrons = 2 - 1 = 1

X has 1 proton, 1 electron and 1 neutron

Number of protons, electrons and neutrons of Y

Atomic number = 17

Atomic number = Number of protons = 17

In a neutral atom (atom with no charge), number of protons = number of electrons

Number of electrons = 17

Mass number = Number of Protons + Number of neutrons

Mass number = 35

35 = 17 + neutrons

neutrons = 35 - 17 = 18

Y has 17 protons, 17 electrons and 18 neutrons

$\frac{1}{2}$ mark each x 6 = 3 marks

(iii)

The type of bond that can be formed belement the two elements is covalent bond

The outermost shell of X is 1 and needs 1 extra to make 2 in order for the first shell to be complete (stable).

The outermost shell of Y is 7 and needs 1 extra to make 8 in order for the third shell to be complete (stable)

Each elements therefore share 1 electron to complete each other or become stable.

The type of bond where the elements involved share electrons is known as covalent bond.

(iv)

X = Hydrogen/H
Y = Chlorine/Cl

$\frac{1}{2}$ mark each x 2 = 1 mark

(i)

Similarities between eukaryotic and prokaryotic cells

They both have:

1. Cell membrane
2. Genetic material /Deoxyribonucleic acid (DNA)
3. Ribosomes
4. Cytoplasm

Any 2 x 1 mark = 2 marks

(ii)

Differences between eukaryotic and prokaryotic cells

Any 2 x 1 mark = 2 marks

(iii)

Organisms made up of Eukaryotic cells

1. Plants or any named plant
2. Animals or any named animal
3. Fungi or any named fungi

Any 1 x $\frac{1}{2}$ mark = 0.5 mark

Organisms made up of Prokaryotic cells

1. Bacteria
2. Archaea

Any 1 x $\frac{1}{2}$ mark = 0.5 mark

(iv)

Impacts of Prokaryotes

1. Pathogens: A small percentage of prokaryotes are human pathogens that can cause disease. These bacteria can contaminate food, leading to foodborne illnesses

2. Mutualistic bacteria: These bacteria live in a symbiotic relationship with humans, helping to protect us

3. Food production: Prokaryotes are used to make cheese, beer, wine, bread, and yogurt

4. Climate change: Prokaryotes metabolize carbon trapped in permafrost, releasing greenhouse gases into the atmosphere

5. Bioremediation: Prokaryotes can remove pollutants from the environment through a process called bioremediation

6. Digestion: Prokaryotes help humans digest food

7. Nutrient production: Prokaryotes produce nutrients that are essential for human survival

8. Immune system: Prokaryotes help train the immune system to function properly

Any 1 x $\frac{1}{2}$ mark = 0.5 mark

Impacts of Eukaryotes

Negative impact

Disease: Some eukaryotic organisms such as Plasmodium which transmit malaria by mosquito bites

Positive impacts

1. Probiotics: Some eukaryotic microbes, such as Saccharomyces boulardii, are considered probiotics and can help with diarrhea

2. Commensal relationship: Some eukaryotic microbes have a commensal relationship with the human body such as the microbes in the gut which benefit from humans but don't cause harm

Any 1 x $\frac{1}{2}$ mark = 0.5 mark

(i)

A seed bed is a local soil environment within which seeds are nursed/planted (1 mark).

(ii)

Types of seed beds

1. Flat beds are uniform, level surface

2. Raised beds are soil elevated into ridges for better drainage and in some cases, to create a warmer soil.

3. Sunken beds have depresions in the soil used to conserve moisture, often in dry regions.

$\frac{1}{2}$ mark each x 3 = 1.5 marks

(iii)

Crops that can be grown on a flat seed bed

1. Wheat
2. Barley
3. Oats
4. Rice
5. Corn/maize
6. Soybeans
7. Beans
8. Peas
9. Potatoes
10. Cucumbers

Crops that can be grown on a raised seed bed

1. Carrots
2. Radishes
3. Beets
4. Lettuce
5. Spinach
6. Tomatoes
7. Peppers
8. Onions
9. Cucumbers
10. Strawberries
11. Garlic

Crops that can be grown on a sunken seed bed

1. Carrots
2. Potatoes
3. Lettuce
4. Onions
5. Spinach
6. Tomatoes
7. Peppers
10. Cucumbers

$\frac{1}{2}$ mark each x 3 = 1.5 marks

(iv)

Advantages of a seed bed

1. Increases the chances of the number of planted seeds that can germiinate per unit area of land

2. It reduces/eliminates competition for the seedlings because weeds and other unwanted plants can easily be controlled/removed

3. It conserves/saves water for the planted seeds/germinating seedlings due to the easy removal/elimination of competing weeds

4. It improves soil aeration, structure and reduces compaction

5. It firms the soil and makes it easier for small seeds to come into contact with water

Any 2 x 1 mark = 2 marks

(i)

Ration is the amount of feed/diet that is given to animals daily/ 24 hour period (1 mark)

(ii)

Factors influencing feed formulation for farm animals

$\frac{1}{2}$ mark each x 3 = 1.5 marks

(iii)

Ways in which water is essential in animal nutrition

1. Water is a nutrient in the body of farm animals
2. It is a solvent in which nutrients are transported round the body
3. It is a medium through which waste products are excreted from the body
4. Most chemical reactions involving enzymatic activities in the body take place in water/body metabolism
5. Loss of water from the surface of the skin and lungs helps in regulating body temperature
6. Water is used in compounding animal feed e.g. pelleting
7. Constituent of fluid and blood
8. Helps in digestion of feed
9. Helps in maintaining body turgidity

$\frac{1}{2}$ mark each x 3 = 1.5 marks

(i)

Pressure is defined as force per unit area applied in a direction perpendicular/normal to the surface of the object.

OR

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

Any 1 x 1 mark = 1 mark

(ii)

Method I

Calculating pressure for each side and comparing

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

Force = 100 N

Area of a rectangle = Length x Breadth

Pressure for side A

Length = 10 m

Breadth = 5 m

Area = 10 m x 5 m = 50 m²

Pressure on side A = $\frac{100}{50}$ = 2 Pa

Pressure for side B

Length = 10 m

Breadth = 7 m

Area = 10 m x 7 m = 70 m²

Pressure on side B = $\frac{100}{70}$ = 1.42857 Pa ≈ 1.4 Pa

Pressure for side C

Length = 7 m

Breadth = 5 m

Area = 7 m x 5 m = 35 m²

Pressure on side C = $\frac{100}{35}$ = 2.85714 Pa ≈ 2.9 Pa

The highest pressure is 2.9 Pa hence the highest pressure will be on side C.

Method II

Calculating area for each side and comparing

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

With a costance force, pressure increases with decrease (smaller) area since area is dividing in the pressure formula.

Hence the side with the smallest area has the highest pressure.

Area for side A = 10 m x 5 m = 50 m²

Area for side B = 10 m x 7 m = 70 m²

Area for side c = 7 m x 5 m = 35 m²

The side with the smallest area is C. Hence the side C will have the highest pressure.

(i)

Life cycle of a grasshopper

Eggs → nymph → adult

1 mark x 3 = 3 marks

(ii)

Why the life cycle of the grasshopper is described as incomplete metamorphosis

1. Unlike complete metamorphosis (egg, larva, pupa, adult), there's no resting pupal stage where dramatic transformation occurs

2. It passes through 3 stages instead of the 4 stages (egg, larva, pupa, adult).

Any 1 x 1 mark = 1 mark

(iii)

Effects of grasshoppers

1. They are major pests to crops

2. Their feces and dead bodies return nutrients to the soil

3. They serve as source of high-protein, nutritious food source for humans

4. They are crucial food source for animals (birds, mammals and invertebrates) in an ecosystem

$\frac{1}{2}$ mark each x 2 = 1 mark

(iv)

Ways of controlling grasshoppers

1. Using predators such as birds, chickens, lizards and spiders to consume large number of nymphs

2. Keep gardens weeded as dense weeds provide ideal habitats

3. Using insecticides/pesticides to kill grasshoppers

4. Using trap strips

5. Planting earlier in the season or using crop rotation to reduce risk of grasshopper damage

$\frac{1}{2}$ mark each x 2 = 1 mark

(i)

Parts of the mammalian tooth

1. Crown (Enamel & dentin)

2. Root

2 x 1 mark each = 2 marks

(ii)

Function of the root

It holds the tooth in place

Function of the enamel

1. It has the hardest tissue in the body and helps to protect teeth from bacteria

2. It also provides strength so the teeth can withstand pressure from chewing

Function of the dentin

It protects the teeth from heat and cold

3 x 1 mark each = 3 marks

(iii)

Proper ways of cleaning the teeth

Floss → Brush → Tongue Scraping/Cleaning → Rinse

4 x $\frac{1}{4}$ mark each = 1 mark

(i)

A producer is an organism, like plants, algae, or some bacteria, that creates its own food (energy-rich organic compounds) from inorganic sources, typically using sunlight (photosynthesis) or chemicals (chemosynthesis), forming the foundation of the food web by converting external energy into a usable form for other organisms

(ii)

A primary consumer is an organism that feeds directly on producers (plants or algae) for energy, occupying the second trophic level in a food chain

(iii)

A secondary consumer is an organism that feeds on primary consumers (herbivores) for energy. They occupy the third trophic level in a food chain, situated above producers (first level) and primary consumers (second level).

(iv)

A food chain is a linear sequence showing a single direct path of energy flow between organisms

(v)

A food web is a complex, interconnected network of multiple, overlapping food chains.

(i)

$\frac{1}{2}$ mark each x 2 = 1 mark

(ii)

$\frac{1}{2}$ mark each x 8 = 4 marks