SAT Subject Biology Practice Question 382: Answer and Explanation
Separates animals with exoskeletons from animals with no exoskeletons
Correct Answer: A
A This is the most difficult of the four questions. Animals with exoskeletons are ants and spiders; all the rest have endoskeletons (lions, bears, apes, humans, and birds) or no skeletons (roundworms and earthworms). If you work toward the left, you find the choices D and E only divide up the animals with endoskeletons but do not separate them from the animals with exoskeletons. Choice C only subdivides phylum Arthropoda; it does not make the separation asked for in the question. This leaves only choices A and B, and choice B separates segmentation from no segmentation; neither of these animals has a skeleton at all. The correct answer is A, which divides phylum Arthropoda (animals with exoskeletons) from phylums Nematoda and Annelida (animals with no exoskeletons).