Why is photosynthesis critical for life on Earth?

Photosynthesis is essential for life on Earth primarily because it produces food and oxygen. This process occurs in plants, algae, and some bacteria, where they convert sunlight, carbon dioxide, and water into glucose and oxygen. The glucose produced serves as a fundamental source of energy for plants and, consequently, for the animals that consume them, forming the base of the food chain.

Moreover, the oxygen released during photosynthesis is critical for the survival of aerobic organisms, including humans, as it is necessary for cellular respiration. This process not only supports life by ensuring the availability of energy-rich compounds but also maintains the balance of gases in the atmosphere, making it vital for sustaining ecosystems.

The other choices do not capture the primary importance of photosynthesis in the same way. While generating heat might occur as a byproduct in some scenarios, it is not the primary function of photosynthesis. Converting carbon dioxide into water is inaccurate, as the process involves converting water and CO2 into glucose and oxygen. Lastly, while decomposing organic material is an important ecological function, it is not a role of photosynthesis but rather of saprophytes and decomposers in the ecosystem. Thus, the production of food and oxygen stands out as the critical reason why photosynthesis is