Choose the correct statements regarding population interactions between two species. A. In both parasitism and commensalism, only one species benefits and the other species is harmed. B. Both species benefit in mutualism. C. Both species benefit in commensalism. D. In parasitism, only one species benefits and the other species is harmed. E. In amensalism, one species is harmed and the other is unaffected. Choose the correct answer from the options given below: (NEET 2026)

Solution & Explanation

Answer: (C) B, D and E only. Evaluating each statement against the NCERT sign-convention table (Table 11.1): A is FALSE — it lumps parasitism with commensalism, but in commensalism the other species is UNAFFECTED, not harmed (so not 'one benefits, other harmed'). B is TRUE — mutualism is (+/+), both species benefit. C is FALSE — commensalism is (+/0); only one benefits, not both. D is TRUE — parasitism is (+/–); one (parasite) benefits, the host is harmed. E is TRUE — amensalism is (–/0); one species is harmed, the other unaffected. Correct-statement set = {B, D, E} → option C. NCERT: Ch 11, p.197, lines 3-10 — "Both the species benefit in mutualism and both lose in competition in their interactions with each other. In both parasitism and predation only one species benefits (parasite and predator, respectively) and the interaction is detrimental to the other species (host and prey, respectively). The interaction where one species is benefitted and the other is neither benefitted nor harmed is called commensalism. In amensalism on the other hand one species is harmed whereas the other is unaffected."