I do believe you are looking for Woody Guthrie :)
The first question is observation, you can't really collect samples on developing muscles or do any of the other things listed
for the second question the answer can vary from B to C...it is important to asses before and after to see how much was actually learned...depending on what the learning experience is, you may SOMETIMES want to asses in between to insure the child or adult is actually retaining information.
If we do not asses our environment, our risk of sickness and disease increases. Any kind of chemical or radiological substances in the air are exposures that can affect our health. Meaning that the air we breathe, foods we eat, the water we drink from, and the products we use can sicken us if they aren't properly cleaned or pure.