Final answer:
A stroke is a sudden illness caused by a blockage of blood flow to the brain. It can result in the death of brain cells and cause various symptoms.
Step-by-step explanation:
A stroke is a sudden illness that is usually caused by a blockage of blood flow to the brain. It occurs when either a blood clot or a broken blood vessel in the brain prevents oxygen and nutrients from reaching the affected area. This lack of blood flow can lead to the death of brain cells and result in various symptoms such as muscle weakness, speech problems, and memory loss.