求问og18的一道题

alexanderwww

求问这篇阅读的第一题不知道conodonts的意思的话，要怎么解题？求nn                        
               
第一题：According to the passage, the anatomical evidence provided by the preserved soft bodies of conodonts led scientists to conclude that

conodonts had actually been invertebrate carnivores

conodonts' teeth were adapted from protective bony scales

conodonts were primitive vertebrate suspension feeders

primitive vertebrates with teeth appeared earlier than armored vertebrates

scientists' original observations concerning the phosphatic remains of conodonts were essentially correct

第一题的答案是d