The condition where one species is harmed whereas the other is unaffected is called
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Amensalism
Two species that live together can affect each other in different ways. Each interaction is marked by its effect on the two species: + for benefit, − for harm and 0 for no effect.
Option (1) Amensalism — Correct. The signs are − and 0: harm to one species, no effect on the other. For example, the bread mould Penicillium makes penicillin, which kills bacteria, but the mould itself gains nothing.
Option (2) Parasitism — Incorrect. The signs are + and −. The parasite gains food and shelter, and the host is harmed. The parasite is not unaffected.
Option (3) Predation — Incorrect. This is also + and −. The predator gains food by killing and eating the prey.
Option (4) Competition — Incorrect. The signs are − and −. Both species lose, because both use the same limited resource.
NCERT Extract:
Population Interactions – “… 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.”