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 You Won't Do for Love (song) have a hit". Caldwell returned to the studio and came up with the final product, which included "What You Won't Do for Love". The song's horn arrangement was written and recorded by Miami arranger Mike Lewis. Caldwell wanted the song to be the sixth track on the album since he figured the Album's second track, "My Flame", which featured him playing guitar, would be the hit. However, TK Records felt confident that "What You Won't Do for Love" would be the breakout hit. When it was released to R&B radio, TK Records did its best to hide the fact that