Normal sleep-wake cycle in a human body is maintained by the secretion of: 
1. Thyroid gland 
2. Thymus gland 
3. Pineal gland 
4. Pituitary gland 

Artificial light, extended work-time and reduced sleep-time disrupt the activity of:

1. Thymus gland

2. Pineal gland

3. Adrenal gland

4. Posterior pituitary gland

A temporary endocrine gland in the human body is:

Identify the hormone with its correct matching of source and function:

The 24-hours (diurnal) rhythm of our body such as the sleep-wake cycle is regulated by the hormone:
1. melatonin
2. calcitonin
3. prolactin
4. adrenaline

Melatonin is secreted by:
1. Pineal gland
2. Skin
3. Pituitary Gland
4. Thyroid