[Campbell Biology P.764] Which of the following statements accurately differentiates sea urc... | Practice Question
Which of the following statements accurately differentiates sea urchins from sea cucumbers based on the provided text?
A: Sea urchins are characterized by a highly reduced endoskeleton, whereas sea cucumbers have prominent spines for protection.
B: Sea urchins have five radially arranged groups of tube feet, while sea cucumbers lack tube feet entirely.
C: Sea urchins are typically spherical with long spines for locomotion and protection, while sea cucumbers are elongated, lack spines, and have a reduced endoskeleton.
D: Sea urchins are flat disks, and sea cucumbers are roughly spherical.
Explanation
The text states that 'Sea urchins are roughly spherical' and have 'long spines, which aid in locomotion as well as protection'. For sea cucumbers, it says they 'are also elongated in their oral-aboral axis, giving them the shape for which they are named' and 'lack spines, and their endoskeleton is much reduced'.