Which enzyme is responsible for creating the covalent bonds that connect the sugar phosphate backbone of the new. dna molecule?

Last week i was assigned a thematic. we have groups of three but the people i was assigned with haven't been in school for days. i would appreciate if anyone can me with my thematic . i highlighted most of the important steps and i circled my thematic topic. in desperate need : ( its due on february 19

How can a geological time scale best be reconstructed? a) comparing vestigial structures in living species b) comparing homologous structures in living species c) examining homologous structures in fossil remains d) examining the written records of scientists from past cultures

Idon’t know the answer and i’ve been stuck on it for a while now skskskskks