What domain includes organisms that have a nucleus?

The Eukarya domain includes eukaryotes or organisms that have a membrane-bound nucleus. This domain is further subdivided into the kingdoms Protista, Fungi, Plantae, and Animalia. Eukaryotes have rRNA that is distinct from bacteria and archaeans.

Nitrogen fixation is carried out by the enzyme nitrogenase, which are found in microbes. Microorganisms that fix nitrogen are bacteria called diazotrophs.  The removal of oxygen or the addition of hydrogen.

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