Think of the composition of each layer of Earth and their relative sizes. Also consider Earth's atmosphere, its oceans, its ice caps, and other materials on its surface. Think about how large or small these parts of Earth are compared to one another.

his research revealed two genetically different groups of prokaryotes, which justified splitting kingdom monera into two kingdoms. the genetic and cellular differences were so great, that these two kingdoms were eventually placed into different domains in the current three-domain system.

the scientific method.

a covalent bond, specfically triple bond