Which characteristic is shared by both echinoderms and chordates?

• A. They both possess jointed appendages.
• B. They both exhibit radial symmetry as adults.
• C. They both are deuterostomes during embryonic development.
• D. They both have a notochord throughout life.

Answer: (C)

Verified step by step guidance

1. Understand the key terms in the question: Echinoderms (e.g., sea stars, sea urchins) and Chordates (e.g., vertebrates like mammals, birds, and fish) are two distinct groups of animals. The question asks for a shared characteristic between these two groups.
2. Review the term 'deuterostomes': Deuterostomes are a group of animals characterized by their embryonic development. Specifically, during early development, the first opening (the blastopore) becomes the anus, and the mouth forms later. Both echinoderms and chordates share this trait.
3. Eliminate incorrect options: Jointed appendages are a characteristic of arthropods, not echinoderms or chordates. Radial symmetry as adults is specific to echinoderms, while chordates exhibit bilateral symmetry. A notochord throughout life is a feature of some chordates but not echinoderms.
4. Focus on the correct answer: The shared characteristic between echinoderms and chordates is that they are both deuterostomes, meaning they share a similar pattern of embryonic development.
5. Conclude by emphasizing the importance of understanding embryonic development patterns in classifying animal groups, as it helps identify evolutionary relationships between different phyla.