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Photosynthesis plays key role in removing carbon dioxide from atmosphere while producing oxygen. It converts water and carbon dioxide gas using energy contained in sunlight. This process helps in growth and development of plants which in turn provides food, wood material and energy. Photosynthesis can be thought as process helpful in development of life cycle supporting ecological functions. Detailed studies on controlling photosynthesis may result in betterment of mankind since it can help in maintaining optimum environmental conditions i.e temperature, forests and green house effects. Marine life is also affected by photosynthesis since many photosynthetic organisms under water promotes interaction between organisms by maintaining corresponding ecosystem.Please let me know if you need any clarification. I'm always happy to answer your questions.
As mentioned in answer, photosynthesis converts carbon dioxide into oxygen. Humans generate carbon dioxide as waste product. Excessive amount of carbon dioxide not only damages respiratory system but can lead to permanent injury of nervous system. It is due to photosynthesis effect, this harmful gas gets converted into oxygen which is essential ingredient of human body and it couldn't survive without it. Moreover, if there is not photosynthesis, plants would gradually die resulting in animals deprived of food. As a result, food chain would get shattered, and it would obviously affect humans, leading to their death. In addition, plants and trees increase beauty of nature making life of humans more delightful and depression free in many cases.
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