If you had the choice of which to hit ,obviously it would be the haystack. The haystack would have more give and would not have rapid deceleration like hitting a hard object like a telephone pole.
The average atomic mass of an element<span> is the sum of the </span>masses of its isotopes, each multiplied by its natural abundance (the decimal associated with percent of atoms<span> of that </span>element<span> that are of a given isotope).</span>
The answer should be a covalent bond.
Molecular biology!! Anatomy would require a organism not just a fossil.
