whats the name of the tube which utilizes rhythmic constriction and relaxation to bring food to the stomach

Chyme is the name given to the partially digested food mass. The pyloric sphincter is a tight valve, and, therefore, very little chyme is allowed to exit the stomach at one time.

Explanation:

1 and 6 for apex

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products