I believe the answer is B
I believe the answer you're looking for is Evolution.
The Electron Transport Chain
You are familiar with the electron transport system in photosynthesis that takes light energy and converts it to chemical bond energy in the form of ATP and NADPH. This electron transport chain in cellular respiration will take the energy stored in NADH and FADH2 during the Krebs cycle and convert it to chemical bond energy in the form of ATP. In eukaryotes, this reaction takes place on the inner mitochondrial membrane. Prokaryotes that undergo aerobic respiration also have an electron transport chain located within their plasma membrane, which may be highly folded similar to the inner membrane of the mitochondrion.
Your missing the blank but there is what you are looking for.
<span>An experiment that fails to prove a hypothesis will often provide a new direction for the researcher.
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