Recent work in classification of life on earth has shown that what were once called prokaryotes are much more diverse than ever suspected. the prokaryotae are now divided into two domains, the eubacteria and the archaeabacteria, as different from each other as either is from the eukaryota. one organism, the blue-green algae or cyanobacteria, has left a fossil record that dates back nearly 3.5 billion years and is among the oldest fossils known. these blue-green algae had cell walls and were photosynthetic. a few hundred years ago, this organism was classified as a plant, then as a protist. today it is classified in the eubacteria because it

A)  Is prokaryotic.

Explanation:

Cyanobacteria is classified as a Eubacteria because it is prokaryotic. Cyanobacteria were once classified as bluegreen algae. Cyanobacteria are prokaryotic though; green algae, like the protists, are eukaryotic. Like the other Eubacteria, their cell walls contain peptidoglycan rather than cellulose.

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.

in the year 2850, humans successfully colonized mars. the martian modules that were constructed could hold only a small population of people. it is now a century later, and the population on mars has grown to 600 people. of the current mars population, 45 people express the recessive phenotype for phenylketon- uria (pku) syndrome (pp genotype).

explanation: