The ultimate source of energy for all life on Earth is the

the sun

explanation: The Sun is the major source of energy for organisms and the ecosystems of which they are a part. Producers such as plants, algae, and cyanobacteria use the energy from sunlight to make organic matter from carbon dioxide and water. This establishes the beginning of energy flow through almost all food webs.

Closing a ring restricts the rotation around individual car bon carbon bonds hope it will you !