What is a delta where are deltas formed

Definition: a triangular tract of sediment deposited at the mouth of a river, typically where it is diverges into several outlets. A river delta is formed from the deposition of sediments carried by a river as the river enters an ocean, sea, lake, or another river. This is because the flow velocity decreases significantly and the fluid loses the ability to transport sediment.

the glands which are associated with each description is given below:

pancreas - is an endocrine and exocrine gland that secretes juices with enzymes for digestion. salivary glands- with protection and digestion in the mouth. liver- secretes bile for digestion.   lachrymal glands - secrete tears to moisten eyes and protect them from particles and infection.   sweat gland -regulates water, salt, and temperature. oil glands - to form a protective barrier on the skin.   goblet cells - secrete mucus for protection.

C- a hypothesis or d- an observation