Ecosystems need producers because they are the start of the food chain.
Producers are consumed by first consumers, the second consumers and so on.
NaCl is dissolved in water so that in a given region or volume the concentration is initially higher in one part than the other l, thus simple diffusion will occur so that there is a net difference or 0, with respect to the concentration of NaCl in a particular volume of water than another. Basically the NaCl will be distributed throughout volume of water.
Produces water should be in the only aerobic section of the diagram. Aerobic respiration end products are carbon dioxide and water. Anaerobic respiration end products are lactic acid in animals and carbon dioxide and ethanol in yeast and plants. (:
B .............................................................................