What should be the same for a correct comparison of population growth?

Correct answer: The time period

The correct answer is A: the time period. To compare population growth fairly, we should observe the change in two populations over the same length of time, such as five years or ten years. If one place is measured for ten years and another for only two years, the comparison may be misleading because the first place has had more time to change. Initial population, density, and area may be useful when calculating or interpreting growth, but they do not replace an equal time period. Option A is correct because growth is a change measured across time. Option B is wrong because two areas can begin with different populations and still be compared if the period and measure are clearly stated. Option C is wrong because density means people per unit area, not the time over which growth occurs. Option D is wrong because area is not the basic condition for comparing change in population. Memory cue: before comparing growth, first compare the number of years.