Concept:Population frequency measures how often an organism appears in a habitat.
Explanation:In ecology, population frequency is the number of times a species is recorded within sample plots or a given area.
It expresses the occurrence or distribution of an organism rather than its total number.
Population density, by contrast, is the number of individuals per unit area.
Population growth rate describes how population size changes over time.
Since the question asks for “number of times an organism occurs,” the most accurate option is frequency.
Answer:B. Population frequency