Populations of the marine snail Littorina saxatilis living on wave-exposed shores often have thicker shells than populations in sheltered coves. To investigate whether this difference is an inherited local adaptation or a developmental response to water movement, marine biologist Aisha Raman and colleagues collected adult females from both environments. The researchers raised the females’ offspring from hatching under either weak or strong simulated water flow while keeping diet and temperature constant. Offspring of exposed-shore females developed thicker shells under both flow conditions, whereas flow strength itself had no measurable effect. Maternal effects—in which a mother’s environment influences her offspring without altering their genes—can persist in the first generation raised in a common environment but generally fade in later generations. The researchers did not breed the laboratory-raised offspring to produce a second generation. Together, these results suggest ______

Which choice most logically completes the text?