In the carbon cycle, the biosphere exchanges what with the atmosphere?

Nitrogen is essential to living organisms to make:

What is the main biological process that consumes carbon dioxide?

The most abundant gas in the atmosphere is?

Which of the following is cycled locally more so than globally?

Which of the following does not cycle in an ecosystem?

Nitrogen fixation is when:

In the nitrogen cycle, the fixation of nitrogen is performed primarily by:

What are the two biological systems involved in cycling carbon to and from the atmosphere?

The phosphorous cycles differs most from any other biogeochemical cycle because:

Ecosystems are dependent on which fundamental pathways?