What can be a long-term benefit of declining death rate in population change?

Correct answer: Average life span may increase

Correct answer: A. The death rate is the number of deaths in a population in relation to its size during a stated period. When mortality declines, people are less likely to die during that period, and improved survival can contribute to a longer average life expectancy or life span. The result depends on broader conditions, so it is described as a possible long-term benefit, not an automatic guarantee for every person. Option A is correct because lower mortality is connected with better survival and potentially longer lives. Option B is wrong because a lower death rate does not make births stop. Option C is wrong because migration is the movement of people and can continue regardless of the death rate. Option D is wrong because death rates do not change the physical area of a region. Memory cue: lower mortality means fewer deaths; over time, survival and life expectancy may rise.