Question

Take three test-tubes. Fill each of them 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 ${\rm{C}}{{\rm{O}}_{\rm{2}}}$?

Answer 1

All animals take oxygen from the atmosphere and breathe out carbon dioxide. Plants release oxygen during photosynthesis and use carbon dioxide.

Complete answer:
Carbon dioxide is a chemical compound made up of two oxygen atoms and one carbon atom. It is also referred to in its ${\rm{C}}{{\rm{O}}_{\rm{2}}}$ formula. It is present at a low concentration in the atmosphere of the Earth and functions as a greenhouse gas.

When the animal respires, it inhales oxygen gas and exhales carbon dioxide into the atmosphere. This carbon dioxide is a waste product formed by the cells of the animal during cell respiration. Cell respiration occurs in the single cells. The test tube A would have the maximum carbon dioxide concentration. The carbon dioxide comes from the snail's breathing. Snail is an organism that inhales oxygen and emits carbon dioxide. Therefore, the carbon dioxide concentration in the test-tube named A increases.

The B test-tube contains a water plant that uses its carbon dioxide for photosynthesis and releases oxygen. There is therefore a higher concentration of oxygen in the B test-tube.
The C test-tube contains both water plants and snails. The carbon dioxide emitted by the snail is used by the plant during photosynthesis, and the oxygen released by the plant is used for the snail respiration.

Therefore, the carbon dioxide concentration in this test-tube is not increased.

Note: When an animal breathes, it absorbs oxygen present in the air and emits carbon dioxide gas. This carbon dioxide is a waste product formed by the cells of the animal during cell respiration. Cell respiration occurs in the single cells. Digested food has the chemical energy contained in it.