False because gravity must be acting upon it. :)
I'm pretty sure it's B because carbon atoms are in all living organisms. They can also be bonded in different varations.
A system that releases heat to the surroundings, an exothermic reaction, has a negative ΔH by convention, because the enthalpy of the products is lower than the enthalpy of the reactants of the system. The enthalpies of these reactions are less than zero, and are therefore exothermic reactions
