What is symbiosis?

• A. A violent interaction
• B. The energy transfer in food webs
• C. A close relationship between species
• D. An interaction that involves abiotic factors only

Answer: (C)

Symbiosis is a close, ongoing relationship between two different species that live in contact with or inside one another. This pairing can take several forms: mutualism, where both partners benefit; commensalism, where one benefits and the other is unaffected; or parasitism, where one benefits at the expense of the other. The key idea is the intimate living-together aspect of two biotic partners.

This concept isn’t about violent interactions, energy transfer in a food web, or interactions that involve only nonliving (abiotic) factors. Those ideas describe different kinds of relationships or processes, whereas symbiosis specifically refers to real, living partnerships between species. For example, bees and flowering plants engage in mutualism, while barnacles on a whale illustrate commensalism, and tapeworms in a host show parasitism.