DENDROLOGY

Detailed explanation-1: -The vast majority of energy that exists in food webs originates from the sun and is converted (transformed) into chemical energy by the process of photosynthesis in plants.

Detailed explanation-2: -The sun is called the ultimate source of energy because: It is the primary source of energy for the earth. With the help of solar energy, all green plants(producers) produce food by the process of photosynthesis. In turn, animals eat plants and use that same chemical energy for all their activities.

Detailed explanation-3: -Sunlight allows plants, algae, and cyanobacteria to use photosynthesis to convert carbon dioxide and water into organic compounds such as carbohydrates. This process is the vital source of organic material in the biosphere. Thus, Sun plays a critical role in the ecosystem.