D. DNA
All organisms contain dna
They give us the energy we need to move and to speak and to live they do that for all the organisms on earth
The ears i think so it can hear predators
Hydrogen bonds exists between the DNA strand and its complementary strand such that; there are two hydrogen bonds between every A and T, and three between every C and G.
Therefore; in this case there will be (2 ×3 ) +(3×3) = 15 hydrogen bonds for the above strand. this is because Adenine binds to Thyamine with two bonds (3 pairs) and Guanine binds to Cytosine with three bonds (3 pairs).