Question

which plant contribute 70-80% of oxygen in atmospheric air

Answer 1

roughly one-third (28%) of the Earth's oxygen but most (70%) of the oxygen in the atmosphere is produced by marine plants. The remaining 2 percent of Earth's oxygen comes from other sources. The ocean produces oxygen through the plants (phytoplankton, kelp, and algal plankton) that live in it.

Answer 2

Marine Plants contribute 70-80% of oxygen in atmospheric air.