The heat required to sustain animals that hibernate comes from the biochemical combustion of fatty acids, one of which is ara chidonic acid. For this acid,

(a) determine its structural formula;

(b) write its balanced combustion reaction;

(c) use average bond energies to estimate the energy released in the combustion reaction; and (d) calculate the mass of arachidonic acid needed to warm a 500 kg bear from 5 oC to 25 oC. (Assume that the average heat capacity of bear flesh is 4.18 J g 1 K 1.)