Final answer:
Dementia refers to the deterioration of intellectual abilities caused by an organic brain disorder. It is a neurodegenerative disorder characterized by the loss of nervous system functioning, usually caused by the death of neurons in the brain. Alzheimer's disease is one type of dementia. Correct option is 2.
Step-by-step explanation:
Dementia refers to the deterioration of intellectual abilities caused by an organic brain disorder. It is a neurodegenerative disorder characterized by the loss of nervous system functioning, usually caused by the death of neurons in the brain. Alzheimer's disease is one type of dementia.