TOEFL Reading: ETS-TOEFL阅读机经 - YRL66Z3XHNZ12TVFL$

In paragraph 2, why does the author provide the information that Arthropoda represents animals with features like jointed legs, an external skeleton, and segmented body parts A. To indicate basic physical differences among insects, crabs, and spiders B. To illustrate the types of physical characteristics considered when classifying animals C. To show the complexity of features that have evolved in organisms D. To demonstrate that some phyla include a wider range of body plans than others do