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

Put each tile to the correct location. categorize each term as something that is typical of a scientific theory, a scientific hypothesis, or both. 1) scientific theories 2) both 3) scientific hypothesis a). a tentative statement used to guide scientific investigations b). makes predictions about future events c). can be tested many independent researches d). based on observations of natural phenomena e) . a well-established highly reliable explanation