Final answer:
NADH and FADH2 are the two reduced cofactors that supply electrons to the electron transport chain in the Inner Mitochondrial Membrane.
Step-by-step explanation:
The two reduced cofactors that supply electrons to the electron transport chain in the Inner Mitochondrial Membrane are NADH and FADH2. These cofactors are produced during cellular respiration and carry high-energy electrons that are used to generate ATP through oxidative phosphorylation. NADH and FADH2 donate their electrons to the electron transport chain, where they are passed along a series of carriers in the inner mitochondrial membrane, ultimately leading to the production of water and the pumping of protons to create a proton gradient.