Test your knowledge of water by answering the following questions. Approximately what percentage of the weight of the human body is water? Approximately what percentage of Earth's surface is covered by water? Where is most of the fresh water on Earth found? What happens to the volume of liquid water when it freezes?

1st- 65%

2nd- 75%

3rd- glaciers and ice caps

4th- it increases

Explanation:

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.