B12 is for lack of strength so mostly it would benefit the elderly ... but it can easily benefit everyone !
Hope this helps! Good luck ;)
There are two mechanisms responsible for these cardiovascular responses during exercise: the exercise pressor reflex, which is a reflex originating in contracting skeletal muscles, and central command, which refers to a parallel output (corollary discharge) from cortical areas involved in generating the motor command to cardiovascular control areas in the brain
The answer is A. it is the safest
D. will be your best option.
It deals with the heart blood and how the lungs fill the cells with oxygen for blood
