Question

select all the correct answers. when doing medical research with human subjects, which four limitations are unavoidable? its often impossible to repeat trials on the same subjects. subjects may report an inaccurate medical history. it can be difficult to control all possible variables. its impossible to come up with testable scientific questions for human subjects. there are ethical or privacy concerns to consider.

Explanation:

All these options represent core unavoidable limitations in human subject medical research: repeating trials on the same subjects is often not feasible due to health/ethical reasons; subjects may misreport medical history; controlling every variable (like lifestyle, genetics) is impractical; and ethical/privacy concerns are inherent to working with human participants.

Answer:

☑️ It's often impossible to repeat trials on the same subjects.
☑️ Subjects may report an inaccurate medical history.
☑️ It can be difficult to control all possible variables.
☑️ There are ethical or privacy concerns to consider.