Answer:

2. ubiquinone

Explanation:

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Ubiquinone transfers the electrons to cytochrome c oxidase during ETS in mitochondria

Option 2

Explanation:

• Electron transport chain is a very essential system for the transportation of the electrons and gaining of energy to form the essential  ATP.

• It take place in the mitochondria of the Cell full staff different type of cytochrome is used during the electron transport system in which Redox reaction take place.

• Ubiquinone transfers the electrons to cytochrome c oxidase

To know more about Electron transport system,

Illustrate the mechanism of electron transport system. - Brainly.in

brainly.in/question/6131373