I think these are the answers:
2. It aids in creating stronger bones.
3. Prevent blood from pooling in the lower extremities.
4. All of these.
5. Complete a self-assessment of where you are at first, and what you want to achieve.
6. Stressor.
Again, these are just guesses. I'm no one to know a lot about this, I just researched somewhat and agreed to the answers I guessed.