Final answer:
Protein serine/threonine phosphatase is the activating phosphatase in the yeast Saccharomyces pombe.
Step-by-step explanation:
The activating phosphatase in the yeast Saccharomyces pombe is called protein serine/threonine phosphatase. Phosphatases are enzymes that remove phosphate groups from proteins, and in this case, it specifically acts on serine and threonine residues. This process of dephosphorylation is important in regulating various cellular processes.