Which of these best demonstrates mutualism between certain types of bacteria and humans? A. Invasive bacteria, located at an area of injury produce toxin that damage healthy tissue of the human body.
B. Bacteria in improperly prepared food is consumed by humans, causing food poisoning.
C. Bacteria become resistant to antibacterial medication that humans use for treatment.
D. Intestinal bacteria obtain nutrients from the gut and produce vitamin K used by humans.

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.

your body is trying to warm itself up. or more precisely, sensors in your skin send messages to your brain to generate heat to your body.