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A culture of bacteria was incubated in nutrient agar at #35^0#C. Samples were taken at intervals in order to estimate the number of bacteria in the population. The data obtained is shown in the graph below.

(a) When was the population of bacteria 350 million?
(b) Account for the shape of the graph between
(i) A and B
(ii) B and C
(iii) C and D
(c) Give three reasons for the shape of the curve between D and E
(d) (i) Suggest what would happen to the population of the bacteria if the temperature was lowered to #0^0#C after incubating for 12 hours
(ii) Give a reason for your answer in (d) (i) above
(e) Give three reasons why it is important to control human population growth rate in kenya?

Answer Text:
a)- 7 hours and 40 minutes
b) i)- Population growth is low .The number of bacteria dividing is few. Bacteria are adjusting to condition or environment. No cells are dividing since they are still immature.
ii)- Population growth rate is very rapid. More cells are dividing due to suitable environment or favourable conditions, few are dying therefore high increase in population. There is plenty of food.
iii)- Population remains constant. No population change, number producing is equal to number dying.
c)- There is accumulation of toxic wastes that kills bacteria.
- There is depletion of nutrients leading to competition of food
- There is stress due to limited space.
d) i)- The population will remain the same
ii)- Temperatures are not conducive for division since low temperature inactivate enzymes hence cell activity stops.
e)- For food to be sufficient for the population
- For provision of social amenities and quality education
- For access to quality health services.