When you breath in you breath in oxygen, which comes from plants, when you breath out, you breath out carbon dioxide, which is what plants breath.
The supporting structure of the cell that is also involved in movement is most likely the cytoskeleton.
B - store and transmit hereditary information
Base on one of the Law of Thermodynamics, the amount of available energy decreases whenever energy is changed in form (which includes a transfer from one trophic level to another). So, as we go from the first trophic level to the top trophic level, the amount of available energy becomes less and less.