What component of earth’s atmosphere exists entirely as a result of photosynthesis? oxygen gas water vapor nitrogen gas carbon dioxide gas

Oxygen gas is a component of Earth's atmosphere and exists entirely as a result of photosynthesis.

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Davinia.

Oxygen Gas

Explanation:

The plants and phytoplanktons performs the process of photosynthesis that adds oxygen into the environment.

The plants use carbon dioxide from atmosphere, water and nutrients from the soil to synthesize glucose in the presence of sunlight.

This process releases oxygen back into the atmosphere as it is a by product of this process.

mendel's first law states that during the formation of reproductive cells , pairs of hereditary factors for a specific trait separate so that offspring receive one factor from each parent.

explanation: