Question

microbe population

part a
what is the area of this graph called where the population reaches its maximum level?
a s - curve
b demographics
c carrying capacity
d exponential growth

part b
which of these would best explain why the microbial population begins to decrease after a period of time?
a organisms moved away to find new mates
d extra food was introduced into the area

Explanation:

PART A

The area where the microbe population reaches its maximum level is called the carrying capacity. The S - curve (option A) is the shape of the growth curve, demographics (option B) is about population characteristics, and exponential growth (option D) is a phase of growth, not the area of maximum population. So the correct option is related to carrying capacity.

If a new predator is introduced into the area (option D, assuming the option text is "a new predator was introduced into the area" as the original text seems to have a typo), it would prey on the microbes, leading to a decrease in their population. Moving to find new mates (option A) or other non - predation/resource - reducing factors would not directly cause a population decrease. So the option related to a new predator introduction (assuming option D has that context) is correct.

Answer:

C. carrying capacity

PART B