4. (a) (i) Explain the condition sickle cell anaemia [3 marks]
(ii) Name three substances that are essential in blood clotting [3 marks]
(b) List four symptoms of vitamin C deficiency [4 marks]
(c) Explain the following terms
(i) Tidal air;
(ii) Complemental air;
(iii) Residual air. [6 marks]
(d) Mention four ways of preventing constipation [4 marks]