Without photosynthesis, Earth would be a vastly different place. Plants, the primary producers in most ecosystems, would cease to exist, leading to a domino effect of extinctions throughout the food chain. Herbivores would lose their main food source, followed by carnivores higher up the chain. Without plants, the atmosphere would lack oxygen, making it impossible for most animals to breathe. Additionally, the carbon dioxide levels would rise unchecked, leading to a runaway greenhouse effect and a scorching, inhospitable planet. In short, without photosynthesis, Earth would be a barren, lifeless world.
