Evolution changing of structures over time.
Photosynthesis is too complex.
Probably inorganic bacteria. Today, all life is found on the third planet from the sun, between 2000 m to 6000 m. Living things are composed of polymers long strings of small molecules like beads on a necklace . Minerals are composed of crystals, which is a packing of atoms in geometric arrays. So life needs energy. Cell walls but no inner nucleus.