What is the key function of sphincters found along the digestive system?
a)they selectively allow and stop passage of partially digested food.
b)they control and direct the quantity of food passing through the digestive organs and prevent backward movement of partially digested food.
c)they improve the muscular strength of the organs involved in digestion.

If I'm right I'd say They control and direct the quantity of food passing through the digestive organs and prevent backward movement of partially digested food. Hope it's helpful.

I’m not really sure

The main role of dna in the  cell is the long-term storage of information. it is often compared to a blueprint, since it contains the instructions to construct other components of the  cell, such as  proteins  and rna molecules.the main function of rna is to carry information of amino acid sequence from the genes to where  proteins  are assembled on  ribosomes  in the  cytoplasm. mark brainliest, my work is good.