It depends on your fitness level and the gradient.
As an average 300 m (altitude) in one hour.
Yes
easyer
As my answer, it will be easier to walk uphill because force pulls your bike down and you might fall off and walking is easier.
All treadmill would give you approximately the same type of cardio workout. To increase your workout, you may want to choose a treadmill that allows you to walk fast or to walk "uphill".
550 cal.
depends on how far you walk, are you going uphill, downhill or is it flat? if you walk on a flat area then you will not burn as much as the other two, uphill you will burn the most. all in all you will not burn a lot of calories unless you walk a pretty good distance and even a couple miles of flat land will only burn around 70 calories. a couple miles uphill could burn over 150.
yes, it is good under doctors observation.
A bear can walk on two legs but only for a few steps even up hill.
not overdrive... it depends how fast ur going
uphill it will be slower downhill it will be faster !! around 60-70 mph
on 2 and fast