Statement A: Pneumotaxic centre is located in the medulla oblongata

Statement B: Pneumotaxic centre moderates the functions of rhythm centre, because it is sensitive to changes in the concentration of O₂ and hydrogen ions.

Pneumotaxic centre is located in the pons. Pneumotaxic centre by itself is not sensitive to changes in the concentration of O₂ and hydrogen ions. A chemosensitive area adjacent to respiratory rhythm centre is sensitive to CO₂ and hydrogen ions. Only peripheral chemoreceptors (carotid bodies and arotic bodies) are sensitive to changes in pO₂.