Question 9
(a) Explain the following terms associated with circulation in humans:
(i) pulmonary circulation; [2 marks]
(ii) systemic circulation [2 marks]
(b) State five diseases of the digestive system [5 marks]
(c) List four ways in which heat is lost from the body [4 marks]
(d) (i) Mention three sources of water used in rural area
(ii) Name four purification stages involved in the water treatment plant. [4 marks]
Observation
Many candidates attempted this question and had varying degree of performance. In performance Question 9(a), the candidates scored low marks while confusing systemic and pulmonary circulation. In Question 9(b) and (c), most candidates answered it correctly. Question 9(d)(i) was answered correctly by majority of the candidates, but many lost vital marks by naming methods of purifying water at home in Question 9(d)(ii).
The expected answers are as follows:
(a) Explanation of terms associated with circulation in humans
(i) pulmonary circulation
This is the movement of deoxygenated blood; from the heart to the lung; and return of oxygenated blood to the heart.
NB: Points to score are demarcated by semicolon (;).
(ii) systemic circulation
This is the movement of oxygenated blood from the heart; and to other parts of the body, and return of deoxygenated blood; to the heart.
NB: Points to score are demarcated by semicolon (;).
(b) Diseases of the digestive system
- Intestinal worms infestation;
- Gastric ulcer/ulcer;
- Constipation;
- Gastroenteritis;
- Gastritis;
- Appendicitis;
- Halitosis;
- Dysentery;
- Diarrhoea;
- Cholera;
- Typhoid;
- Cancer of the digestive system;
- Hemorrhoid/ Piles.
NB: Spellings must be correct to score.
(c) Ways in which heat is lost from the body
- Conduction;
- Evaporation of sweat from skin surface/Physical exercise;
- Through expired air/respiration;
- Urination;
- Passing of faeces;
- Convection;
- Radiation.
(d) (i) Sources of water used in rural areas
- River/stream water;
- Spring water;
- Well water;
- Rain water;
- Borehole water.
(ii) Purification stages involved in the water treatment plant
- Collection of water in a coarse grid;
- Filtration;
- Flocculation/addition of Alum/coagulation;
- Chlorination;
- Storage;
- Sedimentation.