1.)Yes X-rays are a form of energy because they are known as a form of light.
2.)Yes X-rays depending on the part of the body being examined does not have enough energy to cause any cell mutations or cancer and the risks of large X-ray exposure depend on age but if you are pregnant ask a doctor before your X-ray because it can possibly harm the baby.
3.)Yes how an X-ray tube works is mainly by a rotor and a few other parts that co-operate with it but what the rotor does is it spins and creates enough magnetic energy to turn into a form of energy and creates an image of whatever you are examining.
4.)I couldn't find too much on this one but in modern X-rays I believe that you can see internal organs in tissues that are damaged.
5.)No they are not used during MRI's X-rays are a form of light and electro-magnetic energy but an MRI is radio waves and a computer that make a very detailed image of the structure of the body.
6.)No X-rays were discovered in 1895 by Conrad Roentgen.
HOPE THIS HELPS MY DUDE
:D