1. Mass extinction: Photosynthesis is the primary source of energy for almost all life on Earth. Plants use sunlight to convert carbon dioxide and water into sugars, which provide the energy they need to grow. Animals, in turn, eat plants or other animals that have eaten plants. Without photosynthesis, the food chain would collapse, leading to a mass extinction of all animals that depend on plants for food.
2. No oxygen: Photosynthesis is also the primary source of oxygen in the atmosphere. During the process, plants release oxygen as a byproduct. Without photosynthesis, the oxygen levels in the atmosphere would quickly decline, leading to the suffocation of all animals that require oxygen to breathe.
Essentially, without photosynthesis, life as we know it would cease to exist.
