Question

Bio-index number means

• A. Natality - mortality
• B. Mortality/natality
• C. Natality $\times$ mortality
• D. Natality/mortality

Answer 1

Answer: (D)

Natality/mortality

Bio-index number is defined as the ratio between natality and mortality.
The natality rate is the rate, at which new individuals are added to a particular population by reproduction (birth of young ones or hatching of eggs or germination of seeds/spores). It is generally expressed as a number of births per 1,000 individuals of a population per year.

The mortality rate is the rate at which the individuals die or get killed. It is the opposite of natality rate. The mortality rate is generally expressed as the number of deaths per 1,000 individuals of a population per year.
Formula for vital index is Natality rate/ Mortality rate X 100
The Vital index determines the normal rate of growth of a population.

So, the correct answer is option D.