Questions and Answers
Which structure in humans occasionally results from the failure of the cervical sinus to close?
Cervical fistulas
What is the main respiratory mechanism in vertebrates?
Lungs
What are the oldest vertebrates that lived in fresh water and had no jaws?
Ostracoderms
What anatomical feature distinguishes arachnids from protochordates?
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Which feature is a point of organization exhibited by annelids and arachnids that excludes them from being considered protochordate origins?
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What evidence suggests a relationship between echinoderms and chordates?
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Which subphylum includes the Ammocoete larva, which was once believed to be an adult protochordate?
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Which characteristic of vertebrates strengthens the hypothesis that they share a common ancestry with protochordates?
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Under which classification are vertebrates grouped based on their embryonic membrane?
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Which group of vertebrates is characterized by the presence of limbs?
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