What is the responsibility of the offense or attack?

Oxygen passes through capillary walls and into interstitial space where cells absorb ? a. nitrogen, b. oxygen, c. carbon dioxide, d. metabolic waste

Vitamin d is unique in that it has a site of synthesis that is different from the location of action, so it is considered to be a click the answer you think is right. enzyme. lipase. nonessential nutrient. hormone?

Me with this i need to get the answer quickly.