Marine animals do not break down water molecules into oxygen, just like we don't. They breathe O2 gas that is in solution in the water.
When a plant feeds on its own food, that food is broken down in the same way that it's broken down in an animals body (including yours): with oxygen. The oxygen is needed to break down the carbohydrate molecules and release the energy stored in those molecules. While a plant is photosynthesizing, its producing more than enough oxygen to break down its own food.
osmosis
CFC's are released into atmosphere. They break the ozone into oxygen molecules.
Anaerobic Respiration
oxygen :)
Once molecule of glucose contains 6 atoms of carbon, 12 atoms of hydrogen and 6 atoms of oxygen.
Carbohidrates are the easiest molecules to break, and when you break molecules you release energy, and heat. So heat is conserved in a molecule, in a way.
No mitochondrion breaks down food molecules in the absence of oxygen. In the absence of oxygen, glycolysis followed by fermentation occurs in the cytoplasm.
Oxygen
Yes, they use it to break down the food molecules into energy.
Cellular Respiration
anaerobic respiration