And that's exactly what it is: a RF Power Combiner simply combines (sum) different signals in a single output. In the above case, the signals are transmitted over port B and C go out through that output (A).
The body mass index (BMI) or Quetelet index is a value derived from the mass (weight) and height of an individual. The BMI is defined as the body mass divided by the square of the body height, and is universally expressed in units of kg/m 2, resulting from mass in kilograms and height in metres.
BMI categories are divided into four different groups. A BMI of less than 18.5 classifies you as underweight. A BMI between 18.5 and 24.9 indicates that you are at a normal weight. This represents the ideal category for women. BMIs between 25 and 29.9 are defined as overweight and a BMI of 30 or greater is considered obese.