Dna is considered to be the molecule of life. which two functions make dna uniquely suited to this role?

DNA (deoxyribonucleic acid) is a molecule which carries genetic information to direct an organism's growth, development, function, and reproduction. Because of such critical functions, it is considered to be the molecule of life. 

Being such, it has 2 characteristics which allow it to perform such functions.

First, DNA replicates (i.e. duplicates), or makes copies of itself before cell division to ensure that the newer cells still carry the same genetic information as the other (and older) cells of the organism, and thus, should be able to carry out the same functions. 

Next, DNA contains genetic codes (in the form of nitrogen-containing nucleotide bases) used in the production of proteins in the organisms's "body." These codes are transcribed and translated by the RNA molecules in cells to produce different combinations of proteins that largely determine the traits, growth, development, etc. of the organism.