B. bats do things to help the Earth
B since they are unrelated
Answer: I believe it is B
Explanation: it doesnt seem to be a flash back, and there doesnt seem to have a details reveiled
John Snow is known as the father of epidemiology.
In this essay "On the Mode of Cholera" he used both reasoned argument along with documentary evidence to show that cholera spread from person to person.
He gave examples of rows of houses on opposite sides to each other, and how all of the members in one row contracted cholera, while only one person on the opposite row contracted the disease.