When doing medical research with human subjects, which four limitations are unavoidable?

The limitations include the following:
1. The privacy of the individuals involved in the the research must be taken into consideration
2. The risk of physical and physiological well being of the person must be taken into consideration.
3. The subject must be made to understand every procedure and the risks involved before testing.
4. Only minimal exposure to risks is allowed and must have been previously tested in animals to avoid deaths.

What is the question? if you were looking to design a method of separating something, you can separate this compound by putting both in water and allowing the water to dissolve the sugar. then pour it into another beaker and evaporate it then boom! salt and sugar : )