What unique ability do DNA molecules have and why is it important?

DNA, the double-stranded molecule, has the unique ability
to replicate itself. That is, DNA can make exact copies of itself. This is important,
for instance, for the function of biological reproduction and cell growth. The
replication function occurs when the hydrogen bond that exists between nucleotide bases
is broken, which results in the two DNA strands existing as separate single strands of
DNA.

The cell then makes available two new complementary
bases (the original nucleotide base having broken hydrogen bonds) that are paired with
the two single DNA strands. The result is the formation of two new double-stranded DNA
molecules built from the original but separated strands plus new
bases.