Question

Why do we use only aquatic plant for this experiment that show oxygen is produced during photosynthesis in the presence of sunlight

Answer 1

because we can see the oxygen coming out from the water so we use only aquatic plants for that text meant that show oxygen is produced during photosynthesis in the presence of Sunlight full stop

Answer 2

aquatic plants gives oxygen in the presence of sunlight
now anyother terestrial plants gives o2 as well but it cannot be seen because o2 is colourless gas...while the o2 given by hydrilla in water could be seen as bubbles