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.
A,B Values with different superscripts are significantly different; P< 0.01. a,b,c Values with different superscripts are significantly different; P<0.05.
