The energy in most ecosystems comes from the sun.
a. true
b. false

answer; the above answer to the above statement is (true)

colors do exist. the color of the sky is actually violet; humans percieve the color of the sky as blue.

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.  

answergaba;