Helicase separates the two strands of DNA at the Replication Fork behind the topoisomerase. The enzyme responsible for catalyzing the addition of nucleotide substrates to DNA in the 5′ to 3′ direction during DNA replication. Hope I’ve helped ;)
The right answer for the question that is being asked and shown above is that: "a.Cyanobacteria are photoautotrophs." The atmosphere that we depend on for our survival is enriched by numerous cyanobacteria. This fact justifies the characteristic of cyanobacteria that is Cyanobacteria are photoautotrophs.