Cigarette smoking decreases speed in track runner, due to the fact that their lungs have black spots. Making it harder for them to breathe. And harder to breathe causing slowing in speed.
I'll give you the first one: it's a reactant of respiration. if you want the other answers just dm me so its easier to communicate
Answer:
Water is made up of H20 thus that is where the fish is getting the oxygen from
Answer:
echidna and Ostriches lay eggs
