What theory refers to the idea that all matter is made of small units of matter that are made of a nucleus, orbited by electrons, and combine to form various
substances?

Atomic Theory

Explanation:

Atomic theory is the scientific theory that matter is composed of particles called atoms.Atoms are made of a nucleus,orbited by electrons, and combine to form various

substances.

there are mainly three domains in biological classification namely; archaea, bacteria, and eukarya.

archaea includes all the prokaryotic cells which are characterized by their lipid membranes. they have branched hydrocarbon which is attached to glycerol through an ether linkage.

bacteria includes all the prokaryotic cells, the cell membrane of which are made up of the unbranched fatty acid chain. in addition, they are attached to glycerol through an ester bond.

eukarya includes all the eukaryotic cells, that is, the cells contain a nucleus and other membrane-bound cell organelles.

they can be autotrophic as well as heterotrophic, unicellular as well as multicellular

they include kingdoms like protista, plantae, animalia, fungi et cetera.

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explanation: