Ballad operas and singspiels were similar because

The answer is they were both sung in the language of the audience. Ballad opera in English Combined spoken dialogue with simple songs accompanied by basso continuo, characters were taken from contemporary life, and plots often featured political satire, words were in vernacular, music was simple and had catchy tunes, developed in England while to singspiel  Employed spoken dialogue and vocal style more like song than elaborate aria, developed in Germany. 

they were both sung in the language of the audience (apex)

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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