Final answer:
In the Meredith Kercher case, two alternative propositions regarding the DNA on the knife were presented.
Step-by-step explanation:
In the Meredith Kercher case, two alternative propositions were put forth concerning the DNA on the knife. The first proposition suggested that the DNA belonged to Raffaele Sollecito, one of the defendants. The second proposition claimed that the DNA could have come from contamination during the forensic analysis.