Mutualism is best described as what?

• A. When one organism benefits at the expense of another
• B. When both organisms benefit
• C. When neither benefits
• D. When one benefits but the other is harmed

Answer: (B)

Mutualism is a type of symbiotic relationship where both organisms gain benefits that improve their survival or reproduction. This best fits a situation in which each participant gets something positive, such as bees getting nectar while helping flowers reproduce, or gut bacteria aiding digestion for the host. The other scenarios describe interactions where one party benefits at the expense of the other, where neither benefits, or where only one benefits while the other is harmed, which are not mutualism.