If there are three test tubes: Test Tube A contains a snail…

If there are three test tubes: Test Tube A contains a snail submerged in water, Test Tube B contains an aquatic plant submerged in water, and Test Tube C contains a snail and an aquatic plant submerged in water. Let’s revisit Test Tube C. If Test Tube C contains both a plant submerged in water and a snail submerged in water, and you make the test tube airtight by connecting a CO2 probe to the test tube, with plenty of light, what will happen to the amount of CO2 in the test tube as time progresses?  

If there are three test tubes: Test Tube A contains a snail…

If there are three test tubes: Test Tube A contains a snail submerged in water, Test Tube B contains an aquatic plant submerged in water, and Test Tube C contains a snail and an aquatic plant submerged in water. If Test Tube B has only an aquatic plant submerged in water, and there is plenty of supplied sunlight, what process or processes will be occurring in Test Tube B as time progresses?