C. because stimuli is how your body responds to something, and in this case, someone's heart rate increases WHEN their blood oxygen drop. Do you see how it responds? ;-)
Answer:
density and color, do not depend on the amount of matter. your welcome
Explanation:
Well, first off the spongy mesophyll does have some chloroplasts, however they are located quite far from the surface of the leaf where most of the chloroplasts are. Therefore they don't get much light and don't contribute a lot to photosynthesis in the leaf. So why should the leaf waste the energy in making chloroplasts if there is not enough light to make them all efficient enough at photosynthesis?
Answer:
Photosynthesis converts carbon dioxide and water into oxygen and glucose. Glucose is used as food by the plant and oxygen is a by-product.
