"Lichens" show which type of association –

Correct option is A

• The fungus provides structure, protection, and water retention.

• The alga or cyanobacterium performs photosynthesis and provides nutrients (carbohydrates) to the fungus.

• Lichens can grow in extreme environments, including rocks, tree bark, and even arid deserts.

• They are bioindicators of air pollution, as they are sensitive to sulfur dioxide (SO₂).

• Commensalism: One organism benefits while the other remains unaffected (e.g., barnacles on a whale).

• Synergism: Two organisms cooperate to produce a greater effect, but they can survive independently (e.g., soil bacteria working together for nitrogen fixation).

• Antibiosis: One organism inhibits or kills another (e.g., Penicillium mold killing bacteria by producing antibiotics).