1. During photosynthesis, chlorophyll is activated by visible light, and an electron is promoted from its ground state to an excited state. In plants, this excited electron goes on to react with carbon dioxide and water, via photo induced electron transfer (PET). However, in the system devised by Cyrille Boyer and colleagues at the University of New South Wales, the excited electron is donated to a monomer, generating a radical, which then goes on to further react and generate polymers through a process known as living radical polymerization.
Which of the following most effectively completes the paragraph above?
A. Inspired by nature, scientists in Australia have united light and chlorophyll to generate a range of polymers that have biomedical applications.
B. One of the challenges in polymer synthesis is achieving control over the length and structure of the polymers generated.
C. Boyer's team has addressed this using a form of living polymerization called reversible addition fragmentation chain transfer, or RAFT, polymerization, which incorporates an agent, normally a thiocarbonlythio compound, as a mediating species.
D. In the absence of a proper electron donor or acceptor it is possible for such molecules to undergo ordinary fluorescence emission.
E. Various architectures, including star-shaped, comb-shaped and ring-shaped polymers can be synthesized in this way.

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