Observation

 

Many candidates failed to state the respiratory surfaces of the listed organisms, some that could state the respiratory surfaces lost marks to wrong spellings. Some even wrote nephridium for earthworm instead of skin/body surface.

Majority of the candidates also could not state the characteristics of respiratory surfaces in organisms. Some could not even spell ‘permeable’ properly.

Some candidates could not draw the gill to the specification given. In fact, most candidates could not apply drawing techniques like title, measurement of size, neatness of labels, clarity of lines, correct spelling of parts labeled and non-use of arrow heads in guidelines.

Some candidates drew the gill in the head of the fish instead of just drawing the gill.

The expected answers are:

1.(a)(i) Table

Organism	Respiratory surface
Tadpole (2 days old)	Gill (External)
Cockroach	Trachea/tracheoles
Domestic fowl	Lung/lungs
Talinum	Stoma/stomata
Earthworm	(moist) Skin surface/body surface
Amoeba	Cell membrane/plasmalemma/body surface

Note: Spellings must be correct to score.

(ii) Characteristic Features of respiratory surfaces
- Large surface area;
- Thin-walled/thin body surface;
- Moist surface;
- Well-ventilated surface;
- Permeable surface;
- Highly vascularised/network of capillaries present.

(b) Diagram of respiratory organ/gill of Tilapia

Title (TL)
Quality (Q)
Clarity of lines (CL)
Size (SZ) (4 cm to 6 cm)
Neatness of labels (NL)
Details (D)
Comma shaped gill (CG)
Gill filaments shown (GF)
Gill arch/bar shown (GA)

Labels (L) Gill raker, gill filament, gill arch/gill bar, gill lamella.
Note:Spellings must be correct to score.