Which of the Following Is an Example of a Mutualistic

Multiple Choice

Which of the following is an example of a mutualistic interaction?

A) Barnacles obtain safe haven by riding on a whale, while the whale is unaffected.
B) A bacterium fixes nitrogen, thereby providing nutrient for a plant, while the plant provides protection for the bacterium.
C) A virus infects a bird, thus reducing the bird's fecundity.
D) Both a and b
E) None of the above