It should be at about 65J. Not sure, hope I helped.
Heat = change in internal energy + Work done The internal energy of a system = heat added and mechanical work done by the system, i.e. U = Q + W rearranging the formula above, will give us: Q = deltaU + W
Q = U - W = 604 kJ - 43.0 kJ = 561,000 J would be the answer.
Mesophyll only occurs in some plants, and not the usual C3 plants that everyone learns about. In fact, mesophyll is mainly used in photosynthesis - for its light dependent reactions (primary reactions). Therefore, I'd say it's c) the structure which stores glucose for later use.