Answer
Four biological criteria of life are organization, cellular composition, metabolism, and reproduction. One clinical criterion is having active brain waves.
Clinical criteria are used for legal status. Therefore, a person can be declared legally dead by the clinical criteria of life while the cells in their body are still biologically alive. An example of this would be a person who is brain dead.
Work Step by Step
There are actually eight criteria of life; organization, cellular composition, metabolism, responsiveness to stimuli, homeostasis, development, reproduction, and evolution.
(1) Organization - Life uses energy to maintain order and organization. A breakdown of this order results in disease and death.
(2) Cellular composition - Living matter is always compartmentalized into one or more cells.
(3) Metabolism - Life takes in molecules from the environment and chemically breaks them down (catabolism) and/or builds them up (anabolism) to use as building blocks for their own structure. Life also extracts energy from the environmental molecules.
(4) Responsiveness to stimuli - Life has the ability to sense and react to environmental stimuli.
(5) Homeostasis - Life maintains relatively stable internal conditions despite changing external/environmental conditions.
(6) Development - An organism changes in form and function over its lifetime.
(7) Reproduction - Life produces copies of itself and passes its genes onto new, younger life (offspring).
(8) Evolution - All living species exhibit genetic change from one generation to the next. This characteristic of life is only seen in the population as a whole and not in a single individual.
Clinical criteria are those criteria that if they are not met, a person can legally be declared dead. One such criterion is having active brain waves. If a person doesn't have any brain waves for 24 hours, has no reflexes, and is on artificial life support to provide respiration and heartbeats, then they can legally be declared dead.
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