The process where the respiratory pump is stopped during swimming as soon as sufficient speed allows water flow across gills is called:

Correct option is B

Correct Answer: (b) Ram jet ventilation
Explanation:
→ Ram ventilation occurs when fish swim fast enough to push water across the gills without actively pumping.
→ Saves energy and increases oxygen uptake efficiency.
→ Common in fast swimmers like tunas and sharks.
Information Booster:
→ Requires continuous movement; stopping can suffocate obligate ram ventilators.
→ Adaptation for high-demand aerobic lifestyles.
→ Enhances sustained swimming performance.
Additional Information: Ventilation refers to active pumping via buccal–opercular movements.