The nematodes lack organs for

✅ Explanation: Nematodes lack specialized organs for both circulation and respiration.
-Circulation: They rely on the movement of fluids within their pseudocoelom (body cavity) and the diffusion of nutrients for transport.
-Respiration: They exchange gases (oxygen and carbon dioxide) directly through their body surface (cuticle).

🔑Key Points:
-Nematodes possess digestive, nervous, excretory, and reproductive systems, but lack a discrete circulatory or respiratory system.
-Nematodes (roundworms) are cylindrical nonsegmented organisms that are found throughout the world both as free-living species and as human and animal pathogens.
-Adult nematodes are comprised of approximately 1,000 somatic cells, and potentially hundreds of cells associated with the reproductive system.
-Nematodes have been characterized as a tube within a tube, referring to the alimentary canal which extends from the mouth on the anterior end, to the anus located near the tail.
-In size, they range from 0.3 mm to over 8 meters. 
-Some examples of Nematodes that commonly spread disease in humans include ascarids (Ascaris), filariasis, hookworms, pinworms (Enterobius), and whipworms (Trichuris trichiura).