The Wear-and-Tear Theory proposes that aging is a result of the gradual deterioration of cells and tissues due to everyday wear and tear.

The Free Radical Theory suggests that aging is caused by the accumulation of free radicals, which are unstable molecules that can damage cells and DNA.

The Programmed Aging Theory proposes that aging is controlled by genetic factors and follows a predetermined biological clock.

The Evolutionary Theory of Aging proposes that aging is a result of natural selection, where genes that promote survival and reproduction early in life are favored, even if they have negative consequences later in life.

The Activity Theory proposes that aging successfully involves maintaining a high level of activity and engagement in various aspects of life.

The Disengagement Theory suggests that older adults gradually withdraw from social activities and relationships as they age.

The Continuity Theory proposes that older adults maintain a sense of continuity in their personality, values, and behaviors throughout their lives.

The Socioemotional Selectivity Theory proposes that older adults prioritize emotionally meaningful relationships and activities, while reducing involvement in less meaningful ones.

The Kübler-Ross model proposes that individuals experiencing grief and loss typically progress through five stages: Denial, Anger, Bargaining, Depression, and Acceptance.

The Dual Process Model of Coping proposes that individuals use two main coping strategies: Problem-Focused Coping, which involves taking steps to address the stressful situation, and Emotion-Focused Coping, which involves managing the emotional distress caused by the situation.

The Functionalist Theory proposes that death serves important functions in society, such as maintaining social order and promoting social change.

The Terror Management Theory proposes that the fear of death is a primary source of anxiety and distress for individuals, and that people engage in various behaviors to manage this fear.

The Existential Theory of Death focuses on the importance of finding meaning and purpose in life, as well as accepting death as an inevitable part of existence.

The Symbolic Interactionist Theory proposes that individuals construct their understanding of death through social interactions and cultural norms, which shape their beliefs and attitudes towards death.

The Symbolic Interactionist Theory proposes that death is a social construction that varies across cultures and societies, and that individuals' understanding of death is shaped by their social interactions and cultural norms.