13. When compared with the blood in the arteries, the blood in the veins...

1 does not move at all
2 is under lower pressure
3 contains more gases
4 contains more water

is under lower pressure

Explanation:

I think because arteries is for oxygenated blood so it flows very fast and the pressure is big but for veins , it is for deoxygenated blood that flows slower than oxygenated blood, so of course the pressure is lower.

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

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~ trueboss72