How does the process of photosynthesis in plants affect human beings? Photosynthesis releases water vapor into the atmosphere and maintains an optimum humidity for survival. Glucose produced during photosynthesis is stored in plant parts and consumed by human beings as food. Oxygen released as a byproduct during photosynthesis is used by human beings for respiration. Plants absorb sunlight for photosynthesis, reducing the temperature of Earth and making it suitable for human habitation.