What layer of the gastrointestinal wall is a thick layer of connective tissue that provides the gastrointestinal tract with much of its elasticity and distensibility?
a) peritoneum
b) mesentery
c) serosa
d) lamina propria
e) submucosa

E) Submucosa

The submucosa is a thick layer of connective tissue that provides the gastrointestinal tract with much of its elasticity and distensibility?

Secretion of the hormone melatonin

Explanation:

Hypothalamus is the small portion of nuclei present in the lower part of the brain. The hypothalamus can be easily identified as it is present between the pituitary gland on the lower portion and the thalamus on the upper portion.  

The hypothalamus is involved in many important functions of the body one of which is homeostasis which is involved in maintaining the internal conditions. The hypothalamus controls other functions by producing hormones which are involved in the food intake, emotional behaviour.

The circadian rhythm of the body is maintained by the hypothalamus but the melatonin hormone is produced by the pineal gland.

Thus, the selected option is correct.