Final answer:
Brain cell death occurs 4 to 6 minutes after clinical death when the cells do not receive oxygen and nutrients due to a stroke or cerebrovascular accident (CVA)
Step-by-step explanation:
In biology, the occurrence described in the question is known as brain cell death after clinical death. When a person experiences clinical death, which is the cessation of breathing and heartbeat, the brain cells begin to die within 4 to 6 minutes due to the lack of oxygen and nutrient supply. This process is caused by a stroke or cerebrovascular accident (CVA), which can occur when an artery in the brain is blocked by a blood clot. When the blood flow is blocked, it results in the death of brain cells.