4. Take three test-tubes. Fill ¾th of each with water. Label them A, B and C. Keep a snail in test-tube A, a water plant in test-tube B and in C, keep snail and plant both. Which test-tube would have the highest concentration of ?
Snail will inhale oxygen and exhale carbon dioxide whereas the plant will inhale carbon dioxide for respiration.
The test with snail and without plant will have maximum carbon dioxide concentration. Therefore, the order of test tube containing is .
Hence, test-tube A will have the highest concentration of .