Which term describes a close, long-term interaction between two different species?

• A. Predation
• B. Competition
• C. Parasitism
• D. Symbiosis

Answer: (D)

Symbiosis is the term for two different species living together in a close, long-lasting association. This broad concept covers various forms of interaction, from mutualism (both benefit, like clownfish and sea anemone) to commensalism (one benefits, the other is unaffected) and parasitism (the parasite benefits at the host’s expense). Predation involves one organism consuming another and isn’t about a long-term living arrangement, while competition is about sharing resources and doesn’t imply a close, prolonged partnership. So the best term for a close, long-term interaction between species is symbiosis, since it specifically describes that enduring association.