Exercise is a subset of physical fitness.
It is very important to control the conditions of an experiment because FAILURE TO DO THIS WILL MAKE THE RESULTS OF THE EXPERIMENT INVALID.
A controlled experiment refers to an experiment that is conducted under controlled conditions. Conducting experiments under controlled conditions helps scientists to minimize the changes in all other variables with the exception of the ones been tested.
Your answer is B, the endocrine system. Hope this helps!
The plasma membrane is composed of the phospholipid bilayer. The phosphilipids have one head and two tails. The head is polar (hydrophilic) as the tail is non-polar (hydrophobic).
