Clinical trials are restricted by ethics because they involve human patients.
B. It involves a human patient
Explanation:
A human life is much more than just a body to be studied under various conditions. Humans are social animals and need to socialize, breathe in fresh air, have a nutritious and balanced diet and a sound sleep in order to live a fruitful life.
Clinical trials are the types of research in which people participate as subjects or hosts in order to test new treatments, effects and various medical conditions.
Some people also volunteer to test how certain external conditions effect human body. They are kept in the conditions which are to be tested for numerous days.
