Three causes of mental illness are :
1. Changes in the structure or Functioning of Brain : Brain controls the behaviour of the body. Any changes in the structure or functioning can lead to mental illness. Structure of brain is also affected by injury or infection. Mental illness also occurs in case of poor supply of blood to the brain. Tumours, excessive and prolonged alcoholism, nutritional deficiencies and degenerative diseases also cause mental illness.
2. Hereditary factors : There are several hereditary factors responsible for mental illness.
3. Stress or emotional factor : Mental illness may be due to chronic emotional stress or deression.
Explain the following :
(i) Grafting
(ii) Vital capacity
(iii) Ureotelism
(iv) Epigeal germination.
