That should be the cell membrane. The cell membrane acts as a filter in and out.
A new DNA strand elongate only in the 5' to 3' direction during DNA replication because the "polarity of the DNA molecule prevents addition of nucleotides at the 3' end" .
DNA replication occurs in the 5' to 3' direction. DNA polymerase can only add nucleotides to the 3' OH group of the growing DNA strand, this is why DNA replication occurs only in the 5' to 3' direction.
DNA polymerase can only add to the 3' end, so the 5' end of the primer remains unaltered. Consequently, synthesis proceeds immediately only along the so-called leading strand.
Hence, the correct answer will be option (B)
To learn more about DNA strand here
brainly.com/question/13542701
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The answer is B. I hope that this helped.
