Section 3 15. List three medical uses for drugs of abuse. 16. What dangerous effects do stimulants have? 17. List three effects of depressants on the body. 18. Why do you think heroin addiction is so difficult to overcome? 19. Describe how hallucinogens affect the mind.

(B) (i) Explain THREE precaution steps during decontamination of biohazard wastes in bag using an autoclave. (ii) Describe TWO materials that will remain undamaged after autoclaving.

(C) State TWO ways in which fermentation process helps to improve [2 marks] quality of food products.

Calculate the cfu/cm \( \mathrm{cm}^{2} \) for a tested surface of 4 cm in length and 3 cm in width if the number of colonies on the agar plate is 96 cfu. (A) \( 8 \mathrm{cfu} / \mathrm{cm}^{2} \) (B) \( 12 \mathrm{cmu} / \mathrm{cm}^{2} \). (C) \( 72 \mathrm{cmu} / \mathrm{cm}^{2} \) (D) \( 128 \mathrm{cmu} / \mathrm{cm}^{2} \)

8 Which of the following is a type of universal media? (A) MacConkey Agar. (B) Baird-Parker Agar. (C) \( \quad \) Mannitol Salt Agar. (D) Trypticase Soy Agar. 9

(A) State ONE example of selective media that can be used to isolate [3 marks] EACH of the following microorganisms. (i) Gram positive bacteria. (ii) Staphylococci spp. (iii) Gram negative bacteria.