When a slice of fresh apple turns a brown color, this is most likely the result of

This is most likely the result of OXIDATION. When an apple is cut open, the cells of the apple are exposed to the atmosphere, the in built defense mechanism inside the apple that is supervised by certain enzymes react to this situation by reacting with oxygen and creating an oxidized brown layer which protects the apple from foreign bodies.

The correct answer is c.

Not only is it the purchase of about 40% of america, it also grounds to on-go our advancement as a civilization.