Test Tube A will have the highest concentration of CO2. This is because test tube A contains snail, snail is an organism that breathes in O2 and breathes out CO2, Hence CO3 concentration is found in test tube A. Test tube B contains a water plant, which takes in CO2 for food synthesis and gives out O2. Hence, more O2 concentration is found in test tube B. Test tube C contains both a snail and a plant, the CO2 produced by the snail is utilized by the plant for its food synthesis and the O2 released by the plant is utilized by the snail for respiration.
Therefore, test tube A has the highest concentration of CO2
