i)

Tilapia/Bony fish

ii)

I → mouth
II → operculum/gill cover
IV → scales/scale
V → lateral line

iii)

Habitat of tilapia/bony fish

1. Fresh water/river
2. Pond/fish pond
3. Brackish water/lagoon
4. Lake

iv)

Adaptation of fish

III (Pectoral Fin) → used for movement/swimming or pitching

VI (Eye) → for (wide) vision/seeing

(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