The answer is 100%. Three are observable, but the fourth is just a carrier.
The answer is D. Extracellular,
the main ions involve in osmoregulation in a cell are sodium and chloride. Intra-and extracellular distribution of K+ is
influenced, for example, by Na+/K+-ATPase
function, pH, Cellular catabolism and anabolism, Insulin and glucose. Parathormone
and calcitriol are important in the homeostatic regulation of phosphates.
The proportion of mottled fish will
increase over time because of the construction company that dumps a load of
gravel in the bottom of the lake which give it a mottled appearance that made
the mottled fish invisible by their major predator which is the wading bird that hunts them
by sight.
It wants you to explain why its a chemical change. Signs of chemical changes are formation of gas bubbles, cloudyness, change in color or odor.