Answer:
This is an example of hypothesis testing.
Explanation:
A hypothesis is assumed to find out a causal relationship between two factors. Here, cheese or milk is independent factor and an upset stomach is a dependent factor. Victor wishes to confirm the causal relationship between stomach upset and intake of cheese or milk; so that her lactose intolerance shall be confirmed. Therefore, this activity is a form of hypothesis testing.
Bacteria and gum disease to fight the infection
An athlete's resting heart rate is lower due to their consistent exercise routine, which strengthens their cardiovascular system so that it can perform efficiently under stress. An average person does not engage in consistent exercise of this type.
The Cholera epidemic happened around the mid 1800's and killed over a million people in Russia alone.