Abbreviations Challenge Window
Detailed Description
Click on a challenge name to view details, instructions, and access the list of structures points included in the challenge.
Sources/Usage
Public Domain.
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
