The correct answer is option 4 - Green plants. Green plants, such as trees, grasses, and algae, are the largest fixators of solar energy on Earth. They possess a pigment called chlorophyll, which allows them to absorb sunlight and convert it into chemical energy through the process of photosynthesis. During photosynthesis, plants use carbon dioxide and water to produce glucose and release oxygen as a byproduct. This glucose is then used as a source of energy for the plant`s growth and various metabolic processes. Green plants play a crucial role in the Earth`s ecosystem as they are primary producers, meaning they convert solar energy into organic matter, providing food and energy for other organisms in the food chain.