The chemicals in the brain that send messages from one nerve ending to
another are called:

The person who utilize the progression principle will keep adding the difficulty of the exercise that he's doing, while the person who does not, will only stay stagnant.  the person that utilize progression principle, will get a stronger endurance because now his body is conditioned to do harsher routines.{the answer was already on verified)

1. b vitamins2. vitamin k3. vitamin d4. examples are walnuts, seeds, tofu5.  total fat, saturated fat, trans fat, cholesterol, sodium, total carbohydrate, dietary fiber, sugars, protein, vitamin a, vitamin c, calcium, and iron.6. 11257. they have to contain reliable information8. less than 10%  9. i didnt read the course so im not surehope that : p