DENDROLOGY

Detailed explanation-1: -Scientists estimate that roughly half of the oxygen production on Earth comes from the ocean. The majority of this production is from oceanic plankton-drifting plants, algae, and some bacteria that can photosynthesize. One particular species, Prochlorococcus, is the smallest photosynthetic organism on Earth.

Detailed explanation-2: -A byproduct of photosynthesis is oxygen. Scientists believe that phytoplankton contribute between 50 to 85 percent of the oxygen in Earth’s atmosphere.

Detailed explanation-3: -Photosynthesis is the process through which plants convert sunlight, water, and carbon dioxide into oxygen and sugar energy. Photosynthesis continuously replenishes oxygen in the atmosphere. Phytoplankton produces roughly half of the oxygen, with the remainder produced by other green plants.