<span>Algae bloom or algal bloom is an obvious appearance or rapid
increase and accumulation of millions of algae and tiny plant-like organisms in
the water. The blooms of these microscopic algae or phytoplankton is the result
of abundant sunlight, nutrients, and the right water conditions. These blooms may take place in freshwater and
in marine environments as well. They come in different colors, cyanobacteria
blooms for instance are often blue-green which literally means that blue-green
algae comes to bloom</span>
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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.
