observable characteristics of rxisting organisms

the ancestral lineage of existing organisms

denodrogram based on DNA characteristics

sexual characteristics.

are always circular

are always linear

can be either circular or linear, but never both within the same cell

can be circular as well as linear within the same cell.

300 $$ \times $$ 10 nm

300 $$ \times $$ 5 nm

300 $$ \times $$ 20 nm

700 $$ \times $$ 30 nm

They require both RNA and DNA

they both need food molecules

they both require oxygen for respiration

both require the environment of a cell to replicate.