Match Column I with Column II:
| Column I | Column II |
| A. Epiphytes | 1. Cattle egret |
| B. Grazing cattle | 2. Orchid on mango tree |
| C. Sea anemone | 3. Clown fish |
| D. Lice | 4. Ectoparasite |
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → A-2, B-1, C-3, D-4
(A) Epiphytes — this matches (2) Orchid on mango tree. An epiphyte is a plant that grows on another plant for support. The orchid gets a place high up in the light, while the mango tree is neither harmed nor helped, so this is commensalism.
(B) Grazing cattle — this matches (1) Cattle egret. As cattle move, they stir up insects from the grass, and the egrets catch them. The egrets gain and the cattle are not affected: another case of commensalism.
(C) Sea anemone — this matches (3) Clown fish. The clown fish lives among the stinging tentacles of the anemone and is safe from predators. The anemone gets no clear benefit, so this is also commensalism.
(D) Lice — this matches (4) Ectoparasite. Lice live and feed on the outer surface of the human body. A parasite that feeds on the outside of its host is an ectoparasite.
NCERT Extract:
Population Interactions – “… Parasites that feed on the external surface of the host organism are called ectoparasites. The most familiar examples of this group are the lice on humans and ticks on dogs. … (iv) Commensalism: This is the interaction in which one species benefits and the other is neither harmed nor benefited. An orchid growing as an epiphyte on a mango branch, and barnacles growing on the back of a whale benefit while neither the mango tree nor the whale derives any apparent benefit. The cattle egret and grazing cattle in close association, a sight you are most likely to catch if you live in farmed rural areas, is a classic example of commensalism. … Another example of commensalism is the interaction between sea anemone that has stinging tentacles and the clown fish that lives among them.”