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.

The Programmed Theory posits that aging is controlled by genetic factors that determine the lifespan of an organism.

The Cross-Linking Theory proposes that aging is a result of the accumulation of cross-links between proteins and other molecules, which leads to decreased flexibility and functionality.

The Mitochondrial Theory suggests that aging is caused by the decline in the function of mitochondria, the energy-producing organelles in cells.

The Telomere Theory suggests that aging is a result of the progressive shortening of telomeres, which eventually leads to cellular senescence and death.

The Neuroendocrine Theory proposes that aging is influenced by changes in the neuroendocrine system, which regulates hormones and other physiological processes.

The Immunological Theory posits that aging is a result of the decline in the immune system, which leads to increased susceptibility to infections and diseases.

Attachment Theory suggests that social support from loved ones can help individuals cope with bereavement by providing comfort and security.

The Grief Cycle Theory posits that individuals progress through a series of stages, such as denial, anger, bargaining, depression, and acceptance, as they cope with loss.

The Dual Process Model proposes that individuals alternate between focusing on the loss (loss-oriented coping) and engaging in activities that promote a sense of normalcy (restoration-oriented coping).

Meaning-Making Theory suggests that individuals cope with bereavement by finding meaning in the loss and integrating it into their life story.

Avoiding reminders of the loss is generally not considered a healthy coping mechanism, as it can hinder the grieving process.

Anticipatory Grief refers to the emotional response to an expected loss, such as the impending death of a loved one.

Physical symptoms related to grief are not typically associated with complicated grief.