Explanation
Correct answer: D.
Choice D is the best answer because it most accurately describes the overall structure of the text. The text begins by mentioning Catherine L. Cardelús, "a researcher who studies canopy soil." The text then provides information about her chosen research topic: the formation of canopy soil in tree branches, the role of canopy soil in preserving a healthy water cycle in rainforests, and Cardelús’s specific interest in "the canopy soils in large choibá trees in rainforests in Costa Rica." Thus, the text introduces a researcher and then gives information about what she researches.
Why the other choices are wrong
Choice A
Choice A is incorrect because the text doesn’t mention any disagreement between researchers, nor does it describe how such a disagreement was resolved.
Choice B
Choice B is incorrect because the text doesn’t present an idea that Cardelús disagrees with; rather, it describes her research interests and the significance of canopy soil.
Choice C
Choice C is incorrect because the text doesn’t compare the sizes of different types of trees over time. While the text mentions "large choibá trees," it doesn’t compare them to any other tree type or discuss changes in tree size over several years.