Answer:
c. to account for two major and distinct prokaryotic groups in addition to eukaryotes.
Explanation:
Microbiologist Carl Woese compared the ribosomal RNA sequence of the small subunit of RNA. Various organisms have structurally different small subunit of the ribosomes. According to Woese the molecular composition of rRNA in closely related organisms should be more similar than in distantly related organisms. He analyzed the 16S rRNA of various organisms and observed that there are two distinct groups of prokaryotes. He divided the prokaryotes among two domains: Bacteria and Archaea. He placed all the eukaryotes in the domain Eukarya.
Because the stomach is lined by a mucous membrane (the gastric mucosa)
I do not believe so because it is genetic, just you can't forever change a feature without plastic surgery or an accident, etc.