Answer:
tar
Explanation:
tar is the reason your lungs go black because it is evaporated into the smoke that you breathe in and is known to be the most known cause of cancer
Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light.In other words, brightness is the perception elicited by the luminance of a visual target. This is a subjective attribute/property of an object being observed and one of the color appearance parameters of color appearance models.
The answer is muscle endurance
