Necrosis refers to the process of premature or unnatural cell death that is not internally regulated by cells. It is triggered by injury or disease and can occur at any point in the life cycle. 

Two examples of necrosis include:

• Frostbite, which is caused by extreme cold conditions that trigger the necrosis of the body’s extremities such as the nose, fingers, and toes
• Gangrene of the limbs, which is caused due to higher risk of injury and infection in individuals with diabetes