Carbon is listed twice my dude :)
Flatworm get most of their oxygen through diffusion.
the answer is B.extinction can be related to a failure to adapt to changes in the environment.
8. Arteries carry oxygenated blood from the heart to the rest of the body, while veins carry deoxygenated blood from the body, back to the heart. Arteries are thick and muscular, while veins aren't as thick, and they have valves.
Osmosis. If the cell has too much salt the cells will swell. let me know if you want me to explain.
