Answer:
A. Decomposing water requires a high activation energy.
Explanation:
The decomposition of water requires a lot of electrical energy or heat input, generated from some primary energy source (fossil fuel, for exemple). This amount of energy has a strong impact on nature and is an expensive process that would increase the economic value of hydrogen f**ls. For this reason, we can conclude that the challenge facing scientists for hydrogen f**l production is that the decomposition of water requires a high activation energy.
