AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
Litmus solution is extracted from lichens (a plant-like organism belonging to the Lichenes group).
Examiners expect the single word "lichens." Litmus is a natural dye obtained from lichens. Note that lichens are symbiotic organisms (fungi + algae), but for CBSE Class 10, the expected answer is simply "lichens."