What general concept does rigor mortis pertain to?

Rigor mortis refers to the postmortem stiffening of the muscles due to a complex series of biochemical processes that occur in the body after death. This process is primarily a biological response to the cessation of metabolic processes and is influenced by several factors including temperature and the state of the individual's health prior to death.

After death, the body begins to break down, and muscular stiffness occurs as a result of chemical changes in the muscle fibers, particularly the depletion of adenosine triphosphate (ATP), which is essential for muscle relaxation. Once the ATP is used up, muscles can no longer relax, leading to the rigid state characteristic of rigor mortis. Thus, identifying rigor mortis as a biological response encompasses both the physiological aspects of life and the changes that occur after death, highlighting the biological nature of this phenomenon.