What is the key function of sphincters found along the digestive system?

The sphincter is the voluntary or involuntary closing and opening of a certain tube or tract inside your body. The sphincter of the digestive tract controls the amount of materials going out of the body. Sphincter controls the amount of food that can empty be emptied into the duodenum.

water is a polar molecule. a chemical bond is a force of attraction between atoms or ions. bonds form when atoms share or transfer valence electrons. atoms form chemical bonds to achieve a full outer energy level, which is the most stable arrangement of electrons. so, false

explanation:

in h2o molecule, two water molecules are bonded by a hydrogen bond but the bond between two h - o bonds within a water molecule are covalent. the greater the electronegativity difference, the more ionic the bond is. bonds that are partly ionic are called polar covalent bonds. nonpolar covalent bonds, with equal sharing of the bond electrons, arise when the electronegativities of the two atoms are equal.