Final answer:
A flock of pigeons in a park is best described as a population, which is a group of the same species living in the same area, according to the levels of organization in ecology. Therefore correct option is B
Step-by-step explanation:
The question asked is regarding the level of organization that describes a flock of pigeons in a park. When considering the levels of organization in ecology, we find that an organism is a single living thing, a population consists of all the organisms of the same species that live in the same area, a community includes all the different populations that live together in an area, and an ecosystem encompasses all the living things, the populations and communities, in an area interacting with all of the nonliving, or abiotic, parts of the environment. Therefore, a flock of pigeons is best described as a population because it is a group of organisms, all of the same species, living in the same area.