High infant and child mortality rates result in lower values of life expectancy at birth than at older ages. This imbalance in life table disappears only when the crossover occurs and it happens when the inverse of the infant mortality becomes equal to the life expectancy at age one.
Explanation:
found this answer on Google (not my own answer I just copied and pasted)
n irrigation system, developed in Iran, that taps into groundwater through a ... the urban center of an Islamic city; it is dominated by a central mosque and bazaar.
