Final answer:
The most inclusive level of organization in nature is the biosphere, which encompasses all ecosystems on Earth.
Step-by-step explanation:
The most inclusive level of organization in nature is the biosphere. The biosphere is the highest level of organization, encompassing all the ecosystems on Earth. It includes land, water, and even parts of the atmosphere. An ecosystem is a community of living organisms interacting with their non-living environment, while a population is a group of individuals of the same species that live in a specific area. Therefore, the biosphere is the most inclusive level, as it encompasses all the ecosystems, populations, and communities within it.