James: Chemists have recently invented a new technique for extracting rhodium, an element necessary for manufacturing catalytic converters for automobiles, from nuclear waste. Catalytic converters function to remove noxious gases from automobile exhaust. The use of nuclear power is ttherefore contributing in at least one way to creating a cleaner environment. Marta: The technique you mention, though effective, is still at an experimental stage, so there has been no shift in the sources of the rhodium currently used in manufacturing catalytic converters.
Marta responds to James's argument by pointing out a fact that James, in drawing his conclusion, did not take into account.