What term describes the death of plant or animal tissues resulting in discolored areas?

The term that describes the death of plant or animal tissues resulting in discolored areas is necrosis. This biological process occurs when cells undergo a form of uncontrolled cell death, often due to factors such as disease, lack of nutrients, or damage. Necrotic tissue can exhibit various discolorations, typically appearing brown or black, as the cells break down and lose their structural integrity.

In comparison, decay refers more broadly to the breakdown of organic matter, typically facilitated by microbial activity in dead organisms, without necessarily highlighting the discolored areas associated with necrosis. Mortality is an overarching term signifying the state of being dead but does not specifically refer to tissue death or discoloration. Decomposition encompasses the entire process of breakdown after death, which involves multiple stages and can include necrosis but is not limited to the discoloration of tissues. Thus, necrosis specifically identifies the localized and immediate effect on tissues, making it the correct term for this situation.