It's science

In science we're learning about the five levels of organization--the first level is an organism, like a zebra or a blackberry bush. 
The next level is a population, which is like a zeal of zebras, or a cluster of blackberry bushes.
After that is a community--so the zebras, and a population of giraffes, maybe, or the blackberry bushes and a population of, say, raspberry bushes.
Then there's an ecosystem--the community plus the abiotic factors, like water and sunlight.
And all those ecosystems make up a biome. 

You following me so far?

Well, I was thinking, maybe I can apply the organization levels to school.

So a student--just one student--is an organism. That's easy.
The student body is the population. Also easy.
The student population, along with the teacher population, is a community. So that's not too hard, either.
Now, the ecosystem. Okay, imagine each classroom, with its student population and teacher population (I know, only one teacher), is part of the ecosystem, and the abiotic factors are things like paper and pencils and desks and textbooks (completing the ecosystem).
And all those classroom-ecosystems make up a biome.

Haha...I am totally getting an A on Monday's test quiz <--one of those.