7, Which of the sentences below best express the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.
A, The population gradually declines when there is no immigration and death exceed births.
B, In time there may be an overall drop in population as the birth rate and death rate fluctuate.
C, The relationship between birth and death rates is an important reason for limiting immigration.
D, If population losses aren’t replaced through immigration, the birth rate may fall below the death rate.