So this here is our sugar. The blue section is the phosphate group and the green section is our nitrogenous base. And this three molecule component is known as a monomer, a nucleotide. And so on this strand, we have one nucleotide a second nucleotide, a third nucleotide. And on the other strand, we also have this one nucleotide, second nucleotide, a third nucleotide. And what it means for these to be complementary is that these bases here are complementary meaning that they can form an optimal arrangement of bonds.