Cells get energy by breaking down food molecules. The process of breaking down food to restore energy to the cells is called Cellular Respiration.
Ocean waters has its own level of density which depends of the climate, temperature and most of all the location where it came from. The more the ocean water absorbs heat the more its density as a result it rises above from cold to hot. So the the water from the Antarctica usually is less dense and then become more dense when it goes to the equator which is more hot.
By controlling what enters and leaves a cell, the cell membrane A) aids in maintaining homeostasis within the cell. Homeostasis is the process by which organisms maintain life through eating, growing, and living in variable conditions. It would not make sense to answer B) because organisms do not control the homeostasis of their external environment. D) also would not be correct because cell's do not control osmosis in the external environment. The membrane does not control osmosis because osmosis is generally a random process of molecular diffusion whereas the membrane acts in a conscious and controlled way.
