Usually under ground springs, or sometimes hollowed earth beneath solid earth where the water pools.
Carbon dioxide and water are released as by-products. (A)
Biological structures like DNA, proteins and cells all depend on molecules. ... Neurotransmitters like epinephrine are pretty simple molecules, but without them our nervous system couldn't work. Oxygen, containing just two oxygen atoms, is a very simple molecule, and it is certainly essential to living things.
Macrominerals and trace minerals.