What is the advantage of having valves in the veins?

ensure blood flows toward your heart

Explanation:

These valves are what ensure blood flows toward your heart. Vein valves work hard, against gravity, to bring the blood that flowed down via arteries back up to your heart. When your vein valves are open and healthy, they are able to do their job properly, as the blood is easily able to flow up.

Why do veins have valves and what is their function? These valves are what ensure blood flows toward your heart. Vein valves work hard, against gravity, to bring the blood that flowed down via arteries back up to your heart.

Explanation: thats the answer i hope this helps you :)

a. by using fur or clothes to trap heat energy near the body

ionic bonds are two oppositely charged ions that attract. a sodium ion has a 1 positive charge; a chloride ion has a 1 negative charge. sodium and chloride have oppostive charged ions that attract which forms an ionic bond. a chemical bond formed when two atoms share electrons is called