Observation

This was one of the most popular questions but majority of the candidates that attempted it could not relate the structures with functions adequately in question 2(a) Many candidates were writing about photosynthesis instead of giving the structures and stating the functions of each structure as required in the question.
Majority of the candidates scored all the marks for question 2 (b). Some candidates wrote iodine as the mineral needed for the proper functioning of bones and red blood cells. Candidates answered 2 (d) (i) and (d) (ii) well, indicating the knowledge of the topic.
                       
 The expected answers are:

(a) Adaptation of leaf for photosynthesis

Broad/flat leaf lamella; exposes large surface area for maximum absorption of light;

Palisade mesophyll cells contain a lot of chloroplast/chlorophyll; for maximum absorption of light;

Position of leaf to stem; for optimum reception of light rays/sunlight;

Thin lamella; allows light penetration into leaf tissue of mesophyll;

Palisade cells are at right angle/perpendicular to the upper epidermis/chloroplasts are arranged in the periphery of the cells; all for easy activation of the chloroplasts for photosynthesis;

Large vacuoles of the palisade cells; store photosynthetic products;

Large intracellular air spaces in the spongy mesophyll; allow oxygen/carbondioxide to diffuse in/out of the chlorophyllus cells/gaseous exchange;

The epidermal cells have thin cell walls; for easy penetration of sunlight to the mesophyll;

Guard cells have chloroplast; for the absorption of sunlight;

The bean-shaped structure of the guard cell; is to allow for gaseous exchange;

The stomata; open easily when it becomes turgid for diffusion of gases/carbondioxide/oxygen;

Xylem; conducts water into the leaves for photosynthesis;                                                        

Phloem; transports manufactured food to other parts of the plant.

NOTE: Structure x1 mark
              Function x1 mark

              Function only does not score; Function must correspond with structure to score.

(b) Mode of feeding of tapeworm
Parasitic mode of feeding; lives in the gut of man/pigs; has hooks/suckers; which enable it attach itself to the lining of the intestine of the host; has a flattened tape-like/ribbon-like body; provide large surface area for easy absorption of digested food;  no alimentary/digestive system.                                                                                                                                       

(c) Mineral elements necessary for the proper functioning of

(i) Bones
Calcium; phosphorus; fluorine                                                                           

(ii) Red blood cells
Iron; copper                                                                                                        

(iii) Thyroid gland
Iodine                                                                                                                         

NOTE: Spelling must be correct to score in (i), (ii) and (iii).

(d) (i) Benefits of including roughages in the diet of humans
-     Stimulates bowel movement/peristalsis;
-     Reduces blood cholesterol/bowel cancer/gall stones/appendicitis/obesity/diabetes mellitus;
-     They do not contribute to weight gain/high blood sugar;
-     It releases glucose slowly;
-     It prevents constipation.                                                                                                                                                        

(ii) Importance of proteins to humans

For the repair of damaged tissues; replacement of worn-out tissues;

For body building;

For growth;

For the supply of the necessary amino acids;

For formation of hormones/enzymes/antibodies/forming fibrinogen necessary for blood clotting.