A mutation is a new element added to the genetic buildup of an organism. this leads to new abilities that makes that organism adapt to different things, this is passed down through the organisms descendants which will help them get through situations other organisms can't, thus helping the entire species evolve.
Idk because we haven't done any
It is called a herd
Im just writing this for the character limit
This is because lactic acid from anaerobic respiration builds up in the muscles. It takes a while to recover from hard exercise, during which time you may still breathe heavily and have a higher heart rate than normal. ... Hard exercise causes a lack of oxygen in cells.
B. Lactase
Hope that helps!