Each system has its own role to perform. For example the respiratory system helps us breathe while the nervous system is connected with our brian. All the systems are different.

The red blood cells in our body help us breathe because they deliver the oxygen from outside to our body. White blood cells help our body fight infection from diseases. So without any cells in our body we wouldn't be able to fight infections and breathe. In other words none of us would be alive.

Right away your body knows that the bone is broken and it sends white blood cells to examine and then heal the broken bone. Wearing a cast is helpful because it pushes the bone together.

After your heart stops beating, certain things in your body happen. One is that your cells burts open because the temperature of the body decreases to 1.5 degrees Fahrenheit. Another thing is that our organs digest themselves because of the enzymes in the pancreas. You also begin to turn white with purple spots, since your circulation has stopped the red blood cells make their way to the part of your body that's closest to the ground. Your body then decomposes.

Every type of laser surgery has a different laser. For example if you were getting a tattoo removed, the laser used is called Q-switched but if surgeons were performing laser eye surgery then they use an excimer laser. So in every laser surgery a different laser is used.

There are two types of curved mirrors, concave and convex. If you were to look in a concave mirror then you would appear bigger but if you were to look in a convex mirror then you would be smaller. For example in corner stores they use convex mirrors to see the whole store.

Laser light is only one colour while normal light is actually all colours (red, blue, purple, yellow, etc.).

White light isn't really how it sounds. It is acutally composed of all the colours of the rainbow. When the light hits something (a prism) that makes it bend all the colours show.