• Cnidarians: Many cnidarian species, such as corals, develop symbiotic relationships with single-celled algae called zooxanthellae. This symbiosis is crucial for the survival and growth of coral reefs.

• Fungi: Fungi are known to form various symbiotic relationships with other organisms, including

  • Mycorrhizal associations with plant roots, where the fungus helps the plant absorb nutrients in exchange for carbohydrates.
  • Lichens are a symbiotic relationship between a fungus and an algae or cyanobacteria.

• Protozoa: Some protozoa living in the digestive tracts of termites and ruminant animals, helping them break down cellulose.

Therefore, all three groups - cnidarians, fungi, and protozoa - have species that can form symbiotic relationships with other organisms.