Respiratory Adaptations: Altitude and Diving · NCERT Biology

Counter-current flow in fish gills refers to:

  1. Blood and water flowing in the same direction
  2. Blood and water flowing in opposite directions
  3. Blood flowing faster than water
  4. Intermittent flow of water over gills
Show answer and explanation

Correct answer: Blood and water flowing in opposite directions

In counter-current flow, blood flows opposite to water direction. This maintains a diffusion gradient for efficient oxygen uptake.

Difficulty: Medium Question 8 of 20

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