|Question 11Verbal

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Over time, marine mollusks called nautilids continually add segments to their shells, and the chemical composition of each segment is influenced by the available materials in the surrounding water when the segment forms. Paleontologist Amane Tajika and colleagues analyzed the septa (the walls between shell chambers) of one male (samples labeled "M") and one female (samples labeled "F") nautilid, finding that sample F07 had the same concentration of oxygen-18 as did water approximately 135 meters deep and that the oxygen-18 concentration in sample M28 matched that of water at approximately 365 meters deep. Tajika et al. concluded that sample F07 formed at a higher point in the water column than did M28.
Which finding, if true, would most directly support the researchers' conclusion?
In nautilids, sex predicts septa growth rate more strongly than does oxygen-18 concentration in the surrounding water.
A
Among nautilids, there is no effect of sex on the uptake of oxygen-18 from water or its deposition in septa.
B
Male nautilids tend to show higher concentrations of oxygen-18 than do female nautilids inhabiting the same point in the water column.
C
Regardless of sex, nautilids spend most of their lives at depths of 50 meters or greater, where oxygen-18 concentrations typically differ from those higher in the water column.
D