What should you do if possible before updating the uefi firmware?

UEFI stands for the Unified Extensible Firmware Interface. It is a specification for a software program that connects a computer's firmware to its operating system (OS). 
Before updating the UEFI firmware if possible you should backup existing UEFI settings, and connect computer to an U-Power Supply.

By water evaporation from the leaves is created a negative pressure at the top of the tree that promotes the ascension  of the water through channels that are called xylem. there are also two molecule forces that are involved: the intra-water molecules cohesion (water molecules stick to each other) and the adhesion when the water molecules stick to the channels they are running in. this is what enables water to go from the roots to the top of a tall tree.