Question

An arthropod has all the following characteristics except

• A. Bilateral symmetry
• B. Pseudocoelom
• C. Three embryonic germ layers
• D. Protostome development

Answer 1

The correct option is B Pseudocoelom

The pseudocoelom can be defined as a fluid-filled body cavity lying inside the external body wall of the nematode that bathes the internal organs, including the alimentary system and the reproductive system. It is not present in arthropods.
Phylum Arthropoda:

• They possess a chitinous exoskeleton that must be shed during growth.
  
• The paired appendages (e.g., legs, antennae) are jointed.
  
• The segmented bodies are arranged into regions, called as tagmata (e.g., head, thorax, abdomen).
  
• They have bilateral symmetry.
  
• The nervous system is ventral (belly) and the circulatory system is open and dorsal (back).