Answer:
Tissue death
Explanation:
Like when a large part of your body tissue dies.
It is use by Eye Care Professionals To check the eyesight of a person.
If u would have visited a eye care centre u would have noticed a chart like this--
If a person can see all the letters from a distance his eyesight is Perfect.If that person misses a letter or a line from the grid eye treatment or spectacles are given to the person for improving their eyesight
C.) amount of energy exerted while performing an exercise