Nhận biết (M1)

Some cosmetics contain silver nanoparticles (Ag-NPs), which can leach into waterways and soils via wastewater. In a 2014 study, Merel J.C. van der Ploeg and colleagues found that Ag-NPs can accumulate in the bodies of red earthworms (Lumbricus rubellus). While bioaccumulation of manufactured nanoparticles may be inherently worrisome, it has been hypothesized that Ag-NP bioaccumulation in invertebrates like L. rubellus could serve a valuable proxy role, obviating the need for manufacturers to conduct costly and intrusive sampling of vertebrate species—such as house mice (Mus musculus), commonly used in regulatory compliance testing—for nanoparticle bioaccumulation, as environmental protection laws currently require.

Which finding, if true, would most directly weaken the hypothesis presented in the text?

• A.

  Given comparable levels of exposure to Ag-NPs, L. rubellus accumulates Ag-NPs at a higher rate than M. musculus does but in a fixed ratio to the rate at which M. musculus does

• B.

  L. rubellus has been shown to accumulate several other types of manufactured nanoparticles in addition to Ag-NPs, whereas M. musculus has been shown to accumulate only Ag-NPs.

• C.

  Ag-NP concentrations in L. rubellus show no reliable correlation with Ag-NP concentrations in M. musculus when the two species are exposed to similar levels of Ag-NPs.

• D.

  Compared with M. musculus, L. rubellus can accumulate detectable Ag-NP concentrations with significantly fewer negative effects.