How do the molecules in the first question combine to form molecules of fat? They combine when water molecules (H2O) are removed from them.
They combine when oxygen molecules (O2) are removed from them.
They combine when water molecules (H2O) are added to them.
They combine when oxygen molecules (O2) are added to them.

these muscles maintain the blood pressure in the vessels. the smooth muscles are innervated by nerves of the autonomic nervous system. when the muscles contract, they cause vasoconstriction of the vessels and increase blood pressure. when the muscles relax, they enable vasodilation of the   blood vessels hence reduce blood pressure.  

thinking it would be fimbriae