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
Need for Speed: Undercover that sort. Chase Linh will tell you [what] you need to do to get on the inside of a racing group in order to get dirt on them, and then after a race she'll say 'We have enough, let's move in.' [But you're left asking: How did that help at all?]" Finally, the in-game frame rate received little praise, and GameSpot particularly criticized the PS3 version for this problem resulting in a lower score on the platform compared to the Xbox 360 and PC versions. "Need for Speed: Undercover" has sold 1.4 million copies in the United States. Need for