2. Western diet possibly causes problems with the appendix - "Appendicitis is uncommon in rural Africa and Asia"
3. Anatomy involved with immune function or microbiome is hard to understand function.
From links:
The peak incidence occurs in the 15- to 24-year-old age group. However older individuals are more likely to have complications and die from the malady. Symptoms of appendicitis in older people frequently are not as clear-cut as are symptoms in younger people.
People with acute appendicitis often think they would feel better if they just could move their bowels. To encourage a bowel movement, they take a laxative. This is a serious mistake, one that may lead to rupture of the appendix.
https://www.sun-sentinel.com/news/fl-xpm-1987-04-14-87012404...
https://www.scientificamerican.com/article/what-is-the-funct...
One of my favourite pastimes with Hacker News is thinking about how commenters have been trained by playing games to follow incentives and game optimisation (gaming the system).
We’ve become slightly more lactose-tolerant!