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.
Levels of prevention organized as spherical systems. (The pyramid does not have four equal sides; strictly mathematically, the pyramid is on an incline. However, for simplicity of understanding it is presented as a four-equal-sided pyramid.)
