What is one visible feature that makes it easy to identify sea cucumbers as echinoderms?

• A. They have spines.
• B. The endoskeleton is not reduced.
• C. They are elongated in the oral-aboral axis.
• D. They move by serpentine lashing of their arms.
• E. They have five rows of tube feet.

Answer: (E)

Verified step by step guidance

1. Understand the characteristics of echinoderms: Echinoderms are a group of marine animals known for their radial symmetry, a water vascular system, and typically having a calcareous endoskeleton.
2. Identify the unique features of sea cucumbers: Sea cucumbers are a type of echinoderm that have a soft, elongated body and are often found on the sea floor.
3. Recognize the common feature among echinoderms: One of the key features of echinoderms is the presence of tube feet, which are part of their water vascular system and aid in movement and feeding.
4. Focus on the specific feature of sea cucumbers: Sea cucumbers have five rows of tube feet, which is a distinctive feature that aligns them with other echinoderms despite their elongated shape.
5. Conclude with the visible feature: The presence of five rows of tube feet is a visible feature that makes it easy to identify sea cucumbers as echinoderms, distinguishing them from other marine organisms.