Question

life does not exist beyond which metre above mean sea level​

Answer 1

The elevation (on the ground) or altitude (in the air) of an item in relation to the average sea level datum, above which life does not exist, is defined as height above mean sea level (AMSL), which is 9000 meters.

What is the Height above sea level:

• Staying deep—up to six miles below the seafloor—might have given some very early life a chance to survive. This is the conclusion of a new study that identified signs of bacteria that are still living today beneath the Mariana Trench, the world's deepest undersea canyon.

• The vertical distance (height, elevation, or altitude) of a site in relation to a historic mean sea level measured as a vertical datum is known as height above mean sea level. It is codified as orthometric heights in geodesy.