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.
The upward arrow shows the leaves were transferred from low light to high light, and the downward arrow shows the leaves were transferred from high light to low light.
