BMR stands for Basal Metabolic Rate, the minimum calorific requirement needed to sustain life in your body when you are resting. It is also called Resting Metabolic Rate (RMR).
Even if you are in bed asleep all day, your body still needs energy to pump blood around the body, maintain body temperature, etc.
No, it does not. Basal Metabolic Rate is estimated using your weight, height and age (see BMR formulas below). BMR is gender specific. BMR Calculator prompts you to enter your activity level in order to calculate the number of calories you need daily to maintain your current weight.
English BMR Formula:
Women: BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) - ( 4.7 x age in years )
Men: BMR = 66 + ( 6.23 x weight in pounds ) + ( 12.7 x height in inches ) - ( 6.8 x age in years )
Metric BMR Formula:
Women: BMR = 655 + ( 9.6 x weight in kilos ) + ( 1.8 x height in cm ) - ( 4.7 x age in years )
Men: BMR = 66 + ( 13.7 x weight in kilos ) + ( 5 x height in cm ) - ( 6.8 x age in years )
Yes, it is. For details, please see "How to increase metabolism?" [1].
Links:
[1] http://www.actabit.com/weight-loss-tips/how-to-increase-metabolism