Question

question 14 correctly identify the event, agent, or process that is responsible for the current atmosphere on earth of 20% oxygen. ozone layer formation volcanic activity photosynthesis the water cycle

Explanation:

Photosynthesis is the process by which plants, algae, and some bacteria use sunlight, carbon - dioxide, and water to produce glucose and oxygen. Over geological time, photosynthetic organisms have been responsible for increasing the oxygen content in Earth's atmosphere to its current level of about 20%. Ozone layer formation is related to the reaction of oxygen molecules with oxygen atoms in the stratosphere and does not directly produce the oxygen in the atmosphere. Volcanic activity releases various gases but not primarily oxygen in a way that accounts for the current oxygen level. The water - cycle is mainly about the movement of water on Earth and has no direct role in producing atmospheric oxygen.

Answer:

Photosynthesis