DNA does two things. first, it controls
the production of proteins. Proteins
determine how traits are expressed. Each
gene in a DNA molecule directs how
particular proteins are made. For example,
some proteins result in brown eyes, and
others result in green eyes. DNA determines
which proteins are created. The second
function of DNA is to be copied and passed
to offspring during reproduction. The genes
that make up DNA pass from parent to
offspring too. This is how offspring inherit
traits from parents.