<span>The internal structue and phylogenetic relationships were not considered in early taxonomic classifications. Early classifications were mostly based on morphological characters like height, shape, color etc. The organisms have evolutionary relationships which were also not considered in earlier classifications.</span>
7.960 x 10 to the 3rd power :)
They play an important role in the control system by sensing defects that occur during essential processes such as DNA replication or chromosome segregation, and inducing a cell cycle arrest in response until the defects are repaired.
