(a) In a garden, it was observed that the leaves of some vegetables were molting and had turned yellow, purple and orange. There was stunted growth of mostly the lower leaves and the vegetables possessed a weak stem. List the elements likely to be deficient in the garden soil. [5 marks]

(b) State three methods that can be adopted by a farmer to improve soil fertility for improved yield. [3 marks]

(c) State four similarities and four differences between the alimentary canal of a bird and a cockroach.
[8 marks]

(d) List four disorders of the alimentary canal of humans. [4 marks]

Candidates did not perform well in this question. Most dodged question (a) while those that attempted it did not correspond the observed traits with the deficient elements. Many candidates also missed vital points in (c). Questions (b) and (d) were well answered. The expected answers are:

The expected answers are:

Deficient elements in the garden soil

Observed traits	Deficient elements
(i) Yellow leaves	Iron/sulphur/nitrogen/magnesium
(ii) Stunted growth	phosphorus/potassium/sulphur/ nitrogen/magnesium/calcium
(iii) Molting leaves	phosphorus
(iv) Weak stem	calcium/sulphur
(v) purple colour	phosphorus
(vi) Orange colour	potassium

Similarities in the alimentary canal of Birds and Cockroach
- Possession of narrow oesophagus;
- Possession of crop;
- Possession of caecum;
- Possession of muscular gizzard;
- Possession of mid-gut/intestine;
- Possession of rectum.

Differences between the alimentary Canal

Bird	Cockroach
-mouth is modified into beak for pecking	mouth modified for chewing and biting;
- tongue is present in the mouth	tongue is absent in the mouth;
- duodenum is present	duodenum is absent;
- alimentary canal is long	alimentary canal is relatively short;
- hindgut terminates into cloaca	hindgut terminates into anus;
- malpighian tubules are not attached to the alimentary canal	malpighian tubules are attached to to the alimentary canal
- liver/pancreas present in the alimentary canal	liver/pancreas absent in the alimentary canal;
- salivary gland absent	salivary gland present.

Note: Points must correspond to score.