The two differences you see when comparing the four chambers of the heart is that the arteries have a thicker wall and veins have thin walls and that the arteries carry oxygenated blood away from the heart which means they get more pressure than veins.
Because their bodies tell them that they need more oxygen and so breathe faster, and try and get the oxygen their body requires and depends on.
Because dna won't bond corectly
A B
Absolute Dating =Method using properties of atoms in rocks and other objects to determine their ages.
Extinct =When there are no longer any living members of a species.
Radiometric =Method of dating rocks when the amounts of parent and daughter materials are measured.
idk if that is what u wanted