Photosynthesis More recent studies, reported in March 2018, also suggest that photosynthesis may have begun about 3.4 billion years ago. The main source of oxygen in the Earth's atmosphere derives from oxygenic photosynthesis, and its first appearance is sometimes referred to as the oxygen catastrophe. Geological evidence suggests that oxygenic photosynthesis, such as that in cyanobacteria, became important during the Paleoproterozoic era around 2 billion years ago. Modern photosynthesis in plants and most photosynthetic prokaryotes is oxygenic. Oxygenic photosynthesis uses water as an electron donor, which is oxidized to molecular oxygen () in the photosynthetic reaction center. Several groups of animals
What would Jesus do? expression has become a snowclone, sometimes for humorous effect. For example, "What Would Jesus Buy?", "What Would Lincoln Do?", "What Would Brian Boitano Do?", "What Would Mary Marvel Do?", "What Would Johnny Cash Do?", and "What would Tintin do?". The term "What Would Jesus Do?" or "WWJD" is also perceived as a fundamental management and leadership principle given Jesus' methodology of going to the marketplace to preach and lead by example. In modern management principles, more academic and professional references are going to the gemba or Management by Walking Around. What would Jesus do? The phrase "What would Jesus do?"