Observation

Many candidates could not answer (b).

Candidates could not give proper answers to the mode of feeding in Euglena and Spirogyra.

Only a few candidates knew how to answer the question on Estuarine habitat.

The candidates that answered (e) could not correspond their answers properly.

The expected answers are:

(a)

Features of the small intestine that increase the rate of absorption of digested food

- Ridges/furrows on inner linings;

- Small finger-like projections/villi;

- Minute projections/microvilli on the villi;

- Thin epithelial lining of the villi;

- Highly vascularised/well supplied with blood;

- Intestine is long/it has a large surface area.

(b)

Fate of glucose formed in a plant during photosynthesis

- Glucose combines with Nitrogen/Sulphur/Phosphorus to form proteins for growth;

- Glucose is stored as starch;

- Glucose is oxidised to form carbon dioxide/water/energy in respiration;

- Glucose is also converted into lipids/cellulose which is stored.

(c) Mode of feeding of

(i)Euglena

- Exhibits both autotrophic and heterotrophic modes of nutrition;

- In autotrophic mode of feeding, the chlorophyll in its stellate chloroplast absorbs sunlight energy

- And the dissolved carbon dioxide in the pond water diffuses into the cell of Euglena

- Inside the chloroplast, the absorbed solar energy/sunlight is used in the synthesis of glucose from water and carbon dioxide

- Glucose is converted into starch and stored in the paramylum granules

- In heterotrophic mode of feeding, it takes in organic matter/diatoms e.t.c.

- Through the gullet;

- And digests it in the reservoir.

(ii) Spirogyra

- Manufactures its own food through photosynthesis;

- Its spiral chloroplast/chlorophyll absorbs the sunlight energy;

- It absorbs carbon dioxide from water/its environment to manufacture food;

- The manufactured food is used;

- while the rest/excess is stored in its pyrenoid in the form of starch.

(d) Characteristics of an Estuarine Habitat

- It is shallow;

- It has a high level of nutrients;

- Salinity/pH/O2 level fluctuates;

- Turbidity is high during rainy season;

- It is affected by tides;

- Species diversity is low;

- Muddy/soft soil/substratum

(e) Differences between an aquatic and terrestrial habitat
Note: Points must correspond to score.

Aquatic habitat	Terrestrial habitat
- Temperature is lower	temperature is higher;
Thoracic	Chest/thorax
- Water is the medium for growth/reproduction	- Organisms are not affected by humidity
- Organisms are affected by tide/waves/water current	organisms are not affected by tide/waves/ water current
- Organisms are not affected by wind action	organisms are affected by wind action;x
- Light affects the distribution of organisms more	light affects the distribution of organisms less;
- Water is abundant	water is not abundant.

Note: Correct location x 1 mark

Correct vertebrae x 1 mark

Vertebrae spellings must be correct to score

(b) Function of

(i) Palisade

- Manufactures food/carries out photosynthesis/site of photosynthesis;.

- Contains chloroplasts for photosynthesis..

(ii) Vascular bundle.

- Contains xylem for transport of water/mineral salts/phloem for translocation of manufactured organic substances/hormones;.

- Provides mechanical support.

(iii) Epidermis

.

- It keeps the leaf’s shape;.

- Reduces water loss/evaporation;.

- Protects the internal structures of a leaf;.

- Contains stomata for gaseous exchange.

(c) Function of

(i)Sieve tube

Translocates/transports manufactured foods to other parts of the plant.

(ii) Cortex

- The cells of cortex store starch;

- Outer cortex cells of green stems contain chloroplasts and make food by photosynthesis/chlorophyllus cortex cells manufacture food.

(iii) Pith

- Cells of pith act as packing/food storage tissues;

- Supports the stem.

(d)Structural differences

(i) External structural differences between stem and root of a maize seedling

Just a few of the candidates could conveniently answer (d). others could not correspond their answers.