yes it dose
no
nobody knows
Oxygen
Flowers do not give out oxygen, the green parts of a plant give out oxygen when the are engaged in photosynthesis.
They give off more oxygen during the day.
oxygen
That is a parasitic plant. An example is cuscuta
Sponges are considered ANIMAL life not plant life. Therefore they do not give off oxygen, they consume it.
A plant does give off Carbon Dioxide at night when there is not enough light for photosynthesis to occur.
Plant cells can give off oxygen when photosynthesis occurs. They give out carbon dioxide when they respire when there is no light available.
I think when they receive carbon dioxide
i recommend that you have a filtration system in the bowl as during the day plants will give off oxygen while it photosynthasises but at night it gives off gasses and the fish needs to the oxygen to breath. the plant will not be enough for the fish and if you do not have the room for a basic filtration system then the bowl is to small for the fish