Which finding, if true, would most directly support the hypothesis pr…

|Question 12Verbal

Source Texts

Text

Some pharmaceuticals contain titanium dioxide nanoparticles (

T i O_{2}

-NPs), which can leach into waterways and soils via wastewater. In a 2014 study, Cheng Tan and Wen-Xiong Wang found that

T i O_{2}

-NPs can accumulate in the bodies of water fleas (Daphnia magna). While bioaccumulation of manufactured nanoparticles may be inherently worrisome, it has been hypothesized that

T i O_{2}

-NP bioaccumulation in invertebrates like D. magna could serve a valuable proxy role, obviating the need for manufacturers to conduct costly and intrusive sampling of vertebrate species-such as Chinook salmon (Oncorhynchus tshawytscha), commonly used in regulatory compliance testing for nanoparticle bioaccumulation, as environmental protection laws currently require.

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

In comparable environments, D. magna and O. tshawytscha display comparable rates of

T i O_{2}

-NP uptake.

Compared with O. tshawytscha, D. magna can tolerate significantly higher

T i O_{2}

-NP concentrations without displaying any negative effects.

It is easier to detect low and harmless concentrations of

T i O_{2}

-NPs in D. magna than it is to detect high and harmful concentrations of

T i O_{2}

-NPs in O. tshawytscha.

T i O_{2}

-NP concentrations in D. magna tend to vary more from individual to individual than do

T i O_{2}

-NP concentrations in O. tshawytscha when the species are exposed to similar levels of

T i O_{2}

-NPs.