Title: Botany.
Question: What are the stems used for in cacti?

Title: MP3.
Question: What kind of file sharing became popular due to the file sizes of MP3s?

Title: Karl Popper.
Question: Which historically significant communist activist was associated with the 1919 riots in which some of Popper's friends were killed?

Title: John Kerry.
Question:
What was released on March 17, 1969?