Answer;
-Birth rate
Step-by-step explanation;
-The birth rate is the total number of live births per 1,000 in a population in a year or period. For example; in one year, 35 giraffes are born to a population.
-A population is defined as a group of individuals of the same species living and interbreeding within a given area. Members of a population often rely on the same resources, are subject to similar environmental constraints, and depend on the availability of other members to persist over time. Scientists study a population by examining how individuals in that population interact with each other and how the population as a whole interacts with its environment.