Correct answer: Option D- DNA ligase
Explanation: In option A, thymine is a nucleotide, so it is present throughout the replication process, wherever it is required. It is added to the newly formed DNA. In option B, Helicase enzyme is active during initiation and elongation stage, as it facilitates the opening of the winded DNA strands. Option C is nucleotidase and it has no role in DNA replication. So, the correct answer is DNA ligase, which is option D.
The okazaki fragments formed during DNA replication are sealed at the end. And in this step, DNA ligase is used. It catalyzes the formation of phosphodiester bond between the nucleotides of okazaki fragments. So it is the last active molecule of the process.
Answer:
Areas where the myelin sheath has degenerated
Explanation:
Multiple sclerosis is a disease of the nervous system where the myelin sheath is damaged, and impairs its ability of conducing signals in the affected nerves, causing serious deficiencies in many life aspects (movements, sensations, cognition etc).
The answer for this should be D
