The pH scale is a very common and important concept. Before moving on into more complex work in science or health care you should now the effect of acids and bases on pH values. Know what neutral pH is, and whether acids increase or decrease pH . To test your knowledge answer the next few questions. Blood pH must stay within a tight range near neutral of 7.1 to 7.4 for proper body system function. A dangerous condition in patients is acidosis. It can induce mental confusion, rapid breathing, and increased heart rate. In acidosis has the blood pH increased or decreased from the normal, neutral range? A. Blood pH has dropped. B Blood pH did not change. (C) Blood pH increased.

34 (A) (i) Explain ONE purpose of air monitoring. (ii) Describe TWO factors that will affect air quality.

Em 1950, a população de girafas numa região do Quénia era de 4600 indivíduos. Sabe-se que a taxa de decrescimento da população é \( 3,5 \% \) por década. Admitindo que a taxa de decrescimento se mantém constante a longo prazo, responda às questões que se seguem.

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) \( 128 \mathrm{cmu} / \mathrm{cm}^{2} \)

Glycerol a) Name the: (i) Process \( X \) (ii) Enzyme \( Y \) (iii) Molecule Z

(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.