I think impact accretion provides thermal energy to the differentiation of different layers in a planetiesimal. Accretion is the process through which planets form as material orbiting some stars gathers together through collisions and gravitational or electrostatic attraction, eventually forming larger and larger bodies. Planetesimals are objects that forms through accretion during the early stages of planet formation. They may combine with one another to form protoplanets and eventually planets.
the process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a by-product.
