Explanation:
PUT is idempotent. PATCH is not guaranteed to be idempotent.

ALSO KNOW (related points):
• What does AJAX allow a web page to do? → Exchange data with the server asynchronously and update parts of the page without a full reload
• What is the main difference between a Single-Page Application (SPA) and a traditional multi-page site? → An SPA loads one HTML shell and updates content dynamically with JavaScript, instead of loading a new page from the server for each navigation
• What is the difference between progressive enhancement and graceful degradation? → Progressive enhancement starts with a working basic version and adds features for capable browsers; graceful degradation starts full-featured and provides fallbacks for older browsers
• To point a domain at a web server's IPv4 address, which DNS record do you create? → An A record