bdd, 2a is correct.
that is why i mentioned 2a saperately below.....
DNA are not alwas in pair, as well, there are secondary DNA structures exist in the genome, where are not parallal......
similiar as human beings, not always in couples.......
danlian de DNA..... :$
similiar as human beings, not always in couples.......
danlian de DNA..... :$
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