We will spend a great deal of time especially in the laboratory emphasizing the fact that science is a means of finding facts via experimentation. Experimentation is all important and the most important part of this is the proper control.
Experiments begin with an hypothesis that subjects itself to an experimental proof.
The August Krough Principle states that there is an animal that is optimally suited for various experiments that will make experimentation easier. Experiments in physiology can also be at any level from molecular to whole animal. Ecologists are interested in energy budgets of animals. What is the energy cost of movement, reproduction, environmental adaption, etc. Toxicologists are interested in the damage caused by chemicals at all levels.