Which of the following have species that can establish symbiotic relationship with other organisms? Select the correct answer using the codes given below.

Answer: (d) 1, 2 and 3

All three groups have symbiotic species.

Statement by statement

1. ✓ YES Corals (cnidarians) host zooxanthellae algae that feed them.

2. ✓ YES Fungi form lichens with algae and mycorrhiza with plant roots.

3. ✓ YES Protozoa in termite guts digest cellulose for them.

The idea

Symbiosis means two different species living closely together. In everyday use, and in this question, it means the kind where both gain, which is mutualism. Each of the three groups has well-known examples.

Cnidarians: coral + algae living in its tissue → Fungi: fungus + alga = lichen; fungus + root = mycorrhiza → Protozoa: single-celled partners in a termite’s gut digest wood for it

The trap

Protozoa are thought of as disease-causers (malaria, amoebiasis), so they get dropped.

Also know

The three kinds of close relation: mutualism (both gain), commensalism (one gains, the other is unaffected) and parasitism (one gains, the other is harmed).