If this is for gradpoint the answer is Retrospective Study :) .
A doctor is a person that is an expert that treats and diagnoses diseases. The doctor is performing an experiment when they perform diagnostic tests to determine illness. Thus, option a is correct.
Diagnostic tests are used to determine the disease, its cause, and its effect on the body of the organism. It is an experimental study to determine the underlying reasons that led to the disease, infection, or injury.
It is a medical examination performed by doctors or health professionals with various devices, tools, and instruments. It identifies the disease and also its cause.
It is an experiment and not an observational study that investigates all the information related to the disease. It uses the observations and symptoms to diagnose.
Therefore, option a. the doctor is performing an experiment.
Learn more about diagnostic tests here:
https://brainly.com/question/3706758
#SPJ2
Your question is incomplete, but most probably your full question was, A doctor performs several diagnostic tests to determine the reason for a patient's illness. The doctor is performing a(n) _________________.
a. Experiment
b. Observational study
