Answer:naturalistic observation
Explanation:
Naturalistic observation is a type of research in which the subjects are observed in their natural environment without any manipulation or intervention by a researcher.
This is usually done if doing a laboratory experiments will be impossible for that type of research or would not yield a true representation of what is being researched.
Scientists believe that subject behave normal or natural in their natural habitat, where they are not disturbed which means one will get a true sense of their behaviour.