Which is the major event in the electron transport chain?

Explanation

The electron transport chain is responsible for the production of ATP through a process called oxidative phosphorylation. As electrons are passed along the chain, a proton gradient is established, and the energy released during this process is used to drive the synthesis of ATP from ADP and inorganic phosphate. This ATP synthesis is the primary purpose of the electron transport chain in cellular respiration. The other options listed (decarboxylation, isomerization, and substitution) are not the major events in the electron transport chain.