Which of the following events may be a result of a new, fatal disease that affects only senior citizens?
a) a decline in the birth rate
b) a narrow band at the bottom of an age structure diagram
c) an increase in the birth rate
d) an increase in the death rate of post-reproductive individuals

D) an increase in the death rate of post-reproductive individuals

Explanation:

The senior citizens represent the individuals that are in their post-reproductive age. Any disease that affects only the old age individuals would reduce their number in the population. Since these old age individuals have crossed their reproductive age and are in post-reproductive age, the death rate of these post-reproductive individuals would be higher in the population.

cardiovascular system

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