Final answer:
A population refers to the total number of people living in certain areas at a specific time. It is the count of individuals of the same species living in the same area and interacting with each other. Population size and population density are important characteristics for understanding and describing populations.
Step-by-step explanation:
A population refers to the total number of people living in certain areas at a specific time. It is the count of individuals of the same species living in the same area and interacting with each other. For example, if we want to know the population of a city, we would count the number of people living in that city at a particular point in time.
Population size (N) refers to the total number of individuals in a population, while population density is the average number of individuals per unit of area or volume. These two characteristics are important for understanding and describing populations. For instance, larger populations may have more genetic variability and potential for adaptation, while population density can affect interactions within a population, such as competition for resources and finding mates.