I love to run or move rapidly by foot for exercise. It really gets my heart rate up.
Yes! running is such a fun way to exercise!
In terms of mechanics the way your body springs as you run is what actually burns the calories. Interesting I know. 
Yes it is! Did you also know that running a lot is good for improving the stability of your bones
All running or just running fast? With so many speeds of running from Jogging to Sprinting it seems like it would be rough on your bones not good for them.
Just regular running. I could see running to fast to be hard on the legs so I just stick to taking it easy
It's though that humans developed the ability to run about 2.6 million years ago in order to hunt. Interesting huh!