WAEC Biology 2021 Theory — Question 9

Model answer

The set-up consists of an inverted funnel over a sprig of an aquatic plant (e.g. Hydrilla/Elodea) submerged in water inside a beaker, with a water-filled test tube inverted over the funnel stem to collect the gas (oxygen/test gas) given off as bubbles from the plant's cut stem, supported by a stand. As photosynthesis proceeds, oxygen bubbles collect at the top of the submerged test tube, which can then be tested with a glowing splint to confirm it relights (indicating oxygen).