Demographic Structure and Characteristics:
Demographic structure refers to the composition of a population in terms of various demographic variables such as age, sex, education, occupation, income, etc. These characteristics are primarily quantitative in nature, which means they can be measured and expressed in numerical terms.

Quantitative Characteristics:
1. Age Distribution: One of the key quantitative characteristics of a population is its age distribution. This includes the percentage of individuals in different age groups such as children, adults, and the elderly.
2. Sex Ratio: Another important quantitative characteristic is the sex ratio, which refers to the number of males per 100 females in a population.
3. Education Level: The level of education attained by individuals in a population is also a quantitative characteristic that can be measured in terms of the percentage of people with primary education, secondary education, or higher education.
4. Income Distribution: Income distribution is another quantitative characteristic that describes the distribution of income levels among individuals in a population.

Qualitative Characteristics:
While demographic structure primarily focuses on quantitative characteristics of a population, there are also qualitative characteristics such as cultural practices, beliefs, values, and traditions that are not captured by demographic variables. These qualitative characteristics are equally important in understanding the dynamics of a population but are not part of demographic structure.
Therefore, demographic structure explains only those characteristics of a population that are quantitative in nature and can be measured and analyzed statistically. Qualitative characteristics, although important, are not typically included in demographic analysis.