What is released into the cell during electron transfer?

as electrons move through the electron transport chain they go from a higher to a lower energy level and are ultimately passed to oxygen (forming water). Energy released in the electron transport chain is captured as a proton gradient, which powers production of ATP by a membrane protein called ATP synthase

because the light is a great source of energy for the plants to survive. (i hope this )

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]