Answer:
i would probally ask them why they dont think its real. I would honestly try to understand. And then i would show them graphs (online of course) about how its affecting the planet and if they still dont listen id probally just fight them
Explanation:
Oxygen and carbon dioxide travels to and from tiny air sacs in the lungs, through the walls of the capillaries, into the blood. Blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs.

Answer:
No, or at least not yet. there small and dont do much improvment. If they were much bigger and sucked better, including some touch-ups here and there, they would have a bigger effect on removing sea urchins.
Explanation:
<span>A plant's plastids contain its chlorophyll, which enables it to photosynthesize. If it lost the plastids, it would not be able to photosynthesize, which is the only way it can get food, so it would die.</span>