The three major characteristics (attributes) of a population are:
Birth Rate (Natality): It refers to the average number of new individuals added to the population through reproduction per unit of time.
Death Rate (Mortality): It refers to the average number of individuals dying in a population during a given period.
Sex Ratio: Instead of being an individual characteristic (male or female), a population has a sex ratio. It is the ratio of the number of males to females in a population (e.g., 55% females and 45% males).
Age Distribution: A population at any given time is composed of individuals of different ages. If the age distribution is plotted for the population, the resulting structure is called an Age Pyramid.