Answer:
The molecule which is considered a substrate in susbtrate-level phosphorilation is PEP (phosphoenolpyruvic)
Step-by-step explanation:
A substrate level phosphorylation is a chemist reaction where you get ATP by ADP + P
A high energy phosphate substrate, yields its high energy phosphate to ADP.
ADP + P ----> ATP.
In glycolysis, the enzyme pyruvate kinase catalyzes the reaction that converts phosphoenolpyruvic acid into pyruvate.