What does necrosis refer to in plants or animals?

Necrosis refers specifically to the death of tissues in plants or animals, resulting in the formation of dead areas. This typically occurs as a response to various stressors, such as infection, injury, or lack of nutrients and oxygen. When tissues die, they can no longer perform their functions, which can lead to further problems in the organism, such as reduced ability to heal or maintain normal physiological processes.

In contrast, the other options touch on different biological processes. The growth of new tissues pertains to regeneration or healing, which is the opposite of necrosis. Photosynthesis refers to the process by which green plants, algae, and some bacteria convert light energy into chemical energy, entirely different from the concept of tissue death. Lastly, the normal aging process of cells involves gradual changes and deterioration, not immediate death as seen in necrosis.