Explanation:

Organism id the lowest level in the ecological levels as it is an individual being having the ability to act and function independently

Population is a group of organisms usually of same species occupying a defined area at a particular time.

A community is a group of different species living and interacting with each other in the same geographical area at the same time.

Ecosystem is a set of living organism living together while interacting with biotic and abiotic components of their environment. It consist of different communities.

Biosphere is the sum of all the global ecosystems.