Compared to arteries, valves have no pulse, have thin walls and have valves that prevent backflow of the blood. The pressure in the veins is less than that of the arteries, hence, there is no pulse. They are nearer to the surface of the skin. It also connects arteries and capillaries which transport blood all throughout the circulatory system.
They do the same thing that all living and breathing things do! They breathe! When they breathe they are doing the same thing you are doing all day everyday. Inhaling oxygen and exhaling carbon dioxide.
I would assume because of where san francisco is i suppose that it just depends on where your located at
In multi-celullar organisms , the cell cycle produces groups of cells that perform the same function. These groups of cells form what it is called a tissue. A tissue is made up of cells that all are specialised to perform the same function. A bunch of tissues form an organ. Organs are more complex in structure and functions.
lots of different organs together form an organ system.
