Why might adding inorganic phosphate to a reaction mixture where glycolysis is rapidly proceeding sustain the metabolic pathway?

The addition of inorganic phosphate helps to sustain the reaction by helping the reaction to occur in a thermodynamically unfavorable manner.

Explanation:

The reaction  of inorganic phosphate with  glucose is an endergonic reaction which is thermodynamically unfavorable as a result reaction need coupling of ATP hydrolysis to take place in biological system because ATP hydrolysis releases huge amount of free energy as a result the overall free energy change of this reaction becomes negative which helps the reaction to proceed in a thermodynamically favorable manner.

       That"s why inorganic phosphate can be used to sustain the rapidly proceeding glycolysis pathway. The addition of inorganic phosphate makes the reaction thermodynamically unvorable.

the answers would be

the first one and the second one