A person is declared dead upon the irreversible ceasing of spontaneous body functions: brain activity, blood circulation, and respiration. Only about 1 percent of a body’s cells have to die in order for all of these things to happen. How can a person be dead when 99 percent of his or her cells are alive?
To explain: How a person can be dead when 99 percent of the person’s cells are alive.
The smallest basic functional unit of life is a cell. Some organisms consist of single cells, which complete all body functioning within one cell. Some organisms consist of multiple cells. They have specific cells for specific functioning. Some cells live and reproduce independently. Others do so as part of a multi-celled organism.