All three groups listed can establish symbiotic relationships with other organisms.

1. Cnidarians: Certain species like corals have a symbiotic relationship with algae, where the algae provides the coral with nutrients through photosynthesis, and the coral provides the algae with protection and access to sunlight.

2. Fungi: Fungi often establish mutual symbiotic relationships with plants, referred to as mycorrhizae. The fungi helps the plant absorb water and nutrients while the plant provides the fungi with sugars and other organic substances.

3. Protozoa: Some protozoa live in a symbiotic relationship with their host organism. For example, termites have protozoa in their gut that helps them digest wood which they cannot do otherwise.

Therefore option 4 including 1, 2 & 3, is the correct answer as all these organisms have species that can establish symbiotic relationships.