1. Which best explains why viruses are not classified by Linnaean taxonomy?

Viruses do not contain any genetic information or a cell wall.
Viruses share many characteristics with several of the kingdoms.
Viruses cannot reproduce outside a host cell and are therefore nonliving.
Viruses lack a protein coat and any metabolic activity.

2. Why might it be more useful to classify Bacteria and Archaea based on their morphology rather than solely on their phylogeny?

Both domains are capable of sharing segments of DNA with unrelated organisms which makes genetic classification difficult.
Classifying them by shape is more practical since each domain has its own unique and distinctive shapes.
Morphological distinctions are easier to represent on paper than phylogenetic relationships.
The genetic make-up of both domains is so similar that it makes it difficult to make genetic distinctions between species.

3.Why might knowledge of the gene and protein sequences of a species be useful in classifying that species?

It would keep the species from being interbred with any other species that might appear physically similar to it.
It would make it possible to compare that species to other species at a level deeper than outward appearance.
It would allow more accurate naming of the species by basing names on genes rather than appearance.
It would prove that all the members of a given species were genetically identical to each other.