A cell needs to transport a certain ion across its cell membrane. In which of these situations can you conclude that energy must be used? A. The ion is moving from high to low concentration. B. The ion is moving from low to high concentration. C. The ion is moving from the inside to the outside of the cell. D. The ion is moving from the outside to the inside of the cell.

both anaerobic and aerobic respiration use glucose (or other carbohydrates), proteins and lipids to produce atp and nadh. cell uses those energy molecules, obtained from food and   breaks them down during the chemical reactions of respiration. in anaerobic respiration, nadh is regenerated to nad+ by enzymes lactate dehydrogenase (lactate is produced, e.g. in muscle cells) or by alcohol dehydrogenase where ethanol is produced (alcohol fermentation), while in aerobic respiration, electrons from nadh are deposited in the mitochondria to regenerate nad+ (electron transport chain. anaerobic respiration produces 2 atp per molecule of glucose compared to aerobic respiration where about 38 atp molecules are produced.

b. the carbon cycle ensures living things have a source of hydrogen

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.

if the hares very faster than they are now, and thus the lynx's hunting success rate drops because it will be harder to catch them, the rate that will change will be the pray-rate. the pray-rate will change because more hares will be able to survive, thus more individuals for reproduction, so the end result will be increasing population of hares.

the predator-rate will remain pretty much the same because there will be more than enough pray, but the hunting success rate is stagnant.