The fluid mosaic model of membrane structure suggests that membranes are composed of a single fluid layer of phospholipids and proteins
are composed of a fluid bilayer of fatty acids with proteins associated on the outer and inner surfaces
are composed of protein molecules embedded in a fluid bilayer of phospholipids
are composed of a fluid phospholipid bilayer sandwiched between two layers of hydrophilic proteins

answer: accepted answer: aquatic animals use the oxygen dissolved in water to carry out respiration. since the amount of dissolved oxygen in water is low as compared to the amount of oxygen in the air, therefore the rate of breathing in aquatic animals is much faster than it is in terrestrial animals.

explanation:

it has to be understood that the sea water contains a huge amount of sodium and chlorine ions and if they enter the cell of the atlantic cod fish, the cell will shrivel and the fish will die. to avoid such a condition, the fish uses active transport for the purpose of removing the ions against the gradient.

explanation:

the atlantic cod is not a maritime osmoconformer. its native application of salts is less than that of the seawater it lives in. it is continually falling water from the gills to the ocean via osmosis.

countering that, the fish is going to be swallowing seawater. but since its internal collection of salts is lower than seawater, the fish will want to go free of excess salt, and since that's going upon a gradient, then active transport, requiring energy, must be used to pump out the salt. much marine fish use the organs to filter out the salt and these fish discharge very straight urine.