List all the places where there are sphincters in the digestive system.

Upper Esophageal Sphincter, Lower Esophageal Sphincter, Sphincter of Oddi, Pyloric Sphincter, Ileocecal Sphincter and Ana.l Sphincter are the sphincter of the digestive system.

Explanation:

Upper Esophageal Sphincter: This sphincter is located near the pharynx and prevent the entry into the esophagus.

Lower Esophageal Sphincter: This is also known as cardiac sphincter and allows the passage of food from the esophagus into the stomach.

Pyloric Sphincter: Pyloric Sphincter is present in stomach and duodenum and regulates the entry of food from stomach to duodenum.

Sphincter of Oddi: This sphincter allows the entry of bile into the small intestine and located at the meeting point of large and small intestine.

Ileocecal Sphincter: Ileocecal Sphincter regulates the entry of chyme into large intestine from the small intestine.

Ana.l Sphincter: This sphincter is present at the end of rectum and helps in evacuation of waste material.

trachea, alveoli, lung capillaries, arteries

estuaries are the partially enclosed coastal bodies of brackish water formed at the mouth of sea where river meets an ocean. it is a transition zone between river and sea water so estuaries are influenced to both marine environment such as tides, waves and to riverine such as flow of fresh water and sediments. the mixing of sea and fresh water provide high level of nutrients, making estuaries a high product habitats.

many estuaries suffers degradation from a variety of human activities like erosion from deforestation, overgrazing, overfishing, drainage and eutrophication.

so from the above statement answers will be

1. false as estuaries are formed due to both brackish and freshwater.

2.true, due to high productivity estuaries are breeding ground for many marine species.

3. direct and indirect activities of man that contribute to pollution and deposition of sediments.