The amount of energy at each trophic level decreases as it moves through an ecosystem. As little as 10 percent of the energy at any trophic level is transferred to the next level; the rest is lost largely through metabolic processes as heat.
I would say the respiratory system (the lungs) fail. The lungs are to receive oxygen and it sends it to the heart.
I am not much of a biology nerd but I am taking an educational guess.
All I can say that the lungs need oxygen. Without oxygen, the heart will stop pumping blood and you will be suffocating with this essential. That is why you should never smoke and actually take great care of your precious body.
Answer:
Dicot stems have their vascular bundles in a ring arrangement. Monocot stems have most of their vascular bundles near the outside edge of the stem. Monocot roots, interestingly, have their vascular bundles arranged in a ring. Dicot roots have their xylem in the center of the root and phloem outside the xylem.