Contemporaneous presence of both oxidized and reduced forms of electron carriers is mandatory in efficient flux by plant electron transport cascades. This requirement is considered as redox poising that involves the movement of electron from multiple sites in respiratory and photosynthetic electron transport chains to molecular oxygen. This flux triggers the formation of superoxide. c... https://www.roneverhart.com/Apple-11-inch-iPad-Pro-Wi-Fi-64GB-Space-Gray-2018-release/