The red pigment in erythrocytes is which transports oxygen.
hemoglobin
phycoerythrin
carotenoid
chlorophyll

Hemoglobin

Explanation:

The blood is a living tissue made up of cells. These cells include red blood cells or erythrocytes, white blood cells or leukocytes, platelets etc. However, the red blood cells or erythrocytes contains a protein that confers its red coloration upon it. This protein is called HEMOGLOBIN.

Hemoglobin is a protein that contains iron (Fe) element in the core of its structure. Hemoglobin is capable of forming a bond with oxygen molecule, hence, it helps the red blood cells to carry oxygen across the body.

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.

what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.