Answer the following question given this paragraph: 

The biosphere includes all living things within all of their environments. It includes every part of the environment where life exists, from the upper reaches of the atmosphere to the top few meters of soil, to the bottoms of the oceans. An ecosystem is made up of the relationships among smaller groups of organisms with each other, and with their environment. Scientists often speak of the interrelatedness of living things, because, according to evolutionary theory, organisms adapt to their environment, and they must also adapt to other organisms in that environment.


Q: What includes all living things within all their environments, including everywhere life exists, from the upper atmosphere, to the top of the soil, to ocean bottoms?

 Choices:

- biome

- community

- habitat

- biosphere

A:
biosphere
