Read the Passage given below and answer the questions:
Most demographic concepts are expressed as rates or ratios – they involve two numbers. One of these numbers is the particular statistic that has been calculated for a specific geographical-administrative unit; the other number provides a standard for comparison. For example, the birth rate is the total number of live births in a particular area (an entire country, a state, a district or other territorial unit) during a specified period (usually a year) divided by the total population of that area in thousands. In other words, the birth rate is the number of live births per 1000 population. The death rate is a similar statistic, expressed as the number of deaths in a given area during a given time per 1000 population. These statistics depend on the reporting of births and deaths by the families in which they occur.

Which of the following demographic indicators would be most useful for comparing the reproductive behaviour of two societies with very different age structures?

Fertility rate

The correct answer is Option 2: Fertility rate

Fertility rate focuses specifically on women in the child-bearing age group and therefore provides a more accurate measure of reproductive behaviour.

Option 1: Crude birth rate. Incorrect. It may be affected by differences in population composition.

Option 2: Fertility rate. Correct. It directly measures reproductive behaviour.

Option 3: Population density. Incorrect. This measures the relationship between population and area.

Option 4: Sex ratio. Incorrect. This measures the number of females per thousand males.