Question 27 from UPSC CSE 2021 - Environment

Question

Which of the following have species that can establish a symbiotic relationship with other organisms?
1. Cnidarians
2. Fungi
3. Protozoa
Select the correct answer using the code given below.

IASCODEX · Accepted Answer

Correct Option: D. 1, 2, and 3

Strategy: Evaluate each biological group (Cnidarians, Fungi, and Protozoa) for well-documented symbiotic relationships. Confirm that corals, mycorrhizal fungi/lichens, and termite-gut protozoa are all known for such associations, validating all statements.

Key Info: **Cnidarians** include marine organisms like corals, sea anemones, and jellyfish. A key symbiotic relationship is between reef-building corals and photosynthetic dinoflagellates (zooxanthellae), which is vital for nutrient cycling and coral reef ecosystems.

**Fungi** are known for mutualistic partnerships. Mycorrhizae involve fungi and plant roots to enhance nutrient uptake, while lichens are stable symbioses between fungi and photosynthetic partners like algae or cyanobacteria. These are crucial for terrestrial ecosystems.

**Protozoa**, though single-celled, also exhibit symbioses. A classic example is protozoa in termite guts that harbor bacteria to break down cellulose, aiding wood digestion. Protozoan symbionts are also found in corals and other animal hosts.

Symbiosis can be mutualism (both benefit), commensalism (one benefits, other unaffected), or parasitism (one benefits at the other's expense). However, all three groups contain species capable of beneficial mutualistic symbiosis in diverse ecosystems.

IASCODEX · Answer

Option A: 1 and 2 only

IASCODEX · Answer

Option B: 2 and 3 only

IASCODEX · Answer

Option C: 1 and 3 only

Which of the following have species that can establish a symbiotic relationship with other organisms? Cnidarians Fungi Protozoa Select the correct answer using the code given below.

Which of the following have species that can establish a symbiotic relationship with other organisms?

Cnidarians

Fungi

Protozoa
Select the correct answer using the code given below.