Final answer:
Nematodes can be free-living, symbiotic, or parasitic. Free-living nematodes live in different habitats and feed on organic matter. Symbiotic nematodes have a mutually beneficial relationship, while parasitic nematodes obtain nutrition from a host.
Step-by-step explanation:
Nematodes, or roundworms, can have different lifestyles. They can be free-living, symbiotic, or parasitic. Free-living nematodes live in various habitats such as freshwater or soil and they feed on bacteria, fungi, protozoans, or decaying organic matter. Symbiotic nematodes have a mutually beneficial relationship with another organism, whereas parasitic nematodes live as parasites and obtain their nutrition from a host organism.