Population trends are based on which factors?

Population trends are influenced by a variety of demographic factors that provide insights into the dynamics of population changes over time. The correct choice highlights several key elements: age structure, survivorship, fertility rates, migration, and life expectancy.

Age structure indicates how many individuals of different ages are in a population, which affects future birth and death rates. For example, a youthful age structure typically leads to higher birth rates, while an aging population may lead to increased mortality and lower birth rates.

Survivorship refers to the likelihood of individuals surviving at different ages and is closely linked to health care, nutrition, and living conditions. It helps to understand how many individuals will live into adulthood or old age, thereby affecting population size and stability.

Fertility rates are crucial for determining how many births occur in a population, which directly impacts growth. If fertility rates are high, the population may grow rapidly; conversely, low fertility rates can lead to population decline.

Migration encompasses the movement of individuals into and out of a population, which can significantly alter its size and demographic composition. For instance, high levels of immigration can boost population numbers and diversity, while emigration may lead to population loss.

Life expectancy, which represents the average number of years individuals are expected to live