You do it before a lab so as to prevent contamination of the materials. You might have things on your hands that might contaminate the experiment and the research. You do it after because you don't want to have things from your experiments on your hands because that can be extremely dangerous.
Answer:
Your a iloveyoutoo because your
What do you mean with that???
A cover letter is based on you, information on why you are seeking the job and why you are qualified