Decades: 320s BC 310s BC 300s BC 290s BC 280s BC 270s BC 260s BC 250s BC 240s BC 230s BC 220s BC
Years: 277 BC 276 BC 275 BC 274 BC 273 BC 272 BC 271 BC 270 BC
Births
Deaths
... the still-excited electrons are transferred to a photosystem I complex, which boosts their energy level to a higher level using a second solar photon. The highly ...