Answer:
Hypothetico-deductive reasoning.
Step-by-step explanation:
Hypothetico-deductive reasoning may be defined as the scientific process of the producing different hypothesis on a particular topic. One of the hypothesis can be taken of the particular topic and be tested scientifically.
Some people think that psychological stress can cause the ulcers, it is a type of scientific hypothesis. This hypothesis was further tested and later found that ulcers occur due to acid resistant bacteria. This investigation correctly determines the hypothetico-deductive reasoning.
Thus, the answer is hypothetico-deductive reasoning.