Target heart rate is defined as the minimum number of heartbeats in a given amount of time in order to reach the level of exertion necessary for cardiovascular fitness, specific to a person's age, gender, or physical fitness.
A. A person is obese if he or she has an excess amount of body fat.
The reason for A and not B is because someone with a lot of muscles could weigh more based on their BMI, which doesn't differentiate between the weight from muscles vs. fat
So the enzymes in your stomach are most likely there to help you disguest your food. Also they make sure everything is good in your stomach.