Sleep is a temporary lapse of consciousness. During sleep, our central nervous system, breath, heart-beat, and muse-tone are slowing down. Human sleep duration varies enormously. Babies sleep 18-20 hours a day, young children 12-14 hours, adults 7-9 hours, and older people 5-7 hours. Some people nowadays suffer from insomnia. These people cannot sleep easily. Insomnia is not an illness. It is a symptom of a sleeping disorder which can be caused by anxiety, depression, and excitement. It cannot be cured without getting rid of the problems which cause it. But temporary, insomnia can be overcome by drinking chamomile tea. What is insomnia? Select one: a. Depression for cannot sleep well b. Difficulty in sleeping c. Excitement before leaving somewhere d. Anxiety before sleeping ​