Abatch of food contaminated with botulism exotoxin, consumed at a family reunion by most of the members of a family, would be an example of a outbreak.

Point source

Explanation:

An exotoxin is a toxic substance secreted by bacteria. The botulism exotoxin is the exotoxin secretes by bacterial strain named as Clostridium botulinum.

Point source outbreak is a condition in which people are exposed to the same source of infection from a pathogen. This may occur due to the consumption of a single meal which is being infected by the pathogen. This may lead to incidences of food poisoning, disease and even mass death.

what's the rest of the question

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".