Most modern systems of classification are based on evolutionary relationships among organisms – that is, on the organisms' phylogeny. Classification systems based on phylogeny organize species or other groups in ways that reflect our understanding of how they evolved from their common ancestors.
The best explanation of why viruses are not classified by the Linnaean taxonomy is due to C. the Virus can't reproduce outside of a host cell, which means that the host is necessary for its survival and reproduction, and without it cannot live on its own accord, so they are considered non-living, that can't metabolize and undergo the essential reactions of their own.
Because both domains are capable of sharing segments of DNA with unrelated organisms which makes genetic classification difficult.
It would make it possible to compare that species to other species at a level deeper than outward appearance
The proteins like hemoglobin and enzymes can be studied to see whether organism which are similar in form can also be related to each other. Its differences found in these proteins' amino acid sequences will present how closely or distantly related an organism is to another.
All I know is that is a evolutionary group
The right answer is A.
There are different types of classifications of bacteria.
The classification of Linnaeus makes it possible to distinguish different levels: the reign, the branch, the family, the genus and the species. That we can associate with the phylogenetic classification.
Another classification, frequently used, corresponds to their reaction in contact with the Gram stain (morpho-tinctorial classification). It is a method to differentiate bacteria based on their staining capacity varying according to the composition of their wall. Thus, the bacteria colored in blue-violet will be said Gram-positive and those in pink Gram-negative.
Finally, they can be classified according to their need for oxygen to survive in aerobic bacteria or anaerobic bacteria.