Which Example is a Mutualistic Interaction

Question

Which example is a mutualistic interaction?
A) Barnacles obtain safe haven by riding on a whale,while the whale is unaffected.
B) A bacterial species lives inside a plant's roots and provides usable nitrogen to the plant,which in turn provides sugar nutrients to the bacteria.
C) A virus infects a bird,thus reducing the bird's fecundity.
D) A wasp lays its egg inside a caterpillar,and the hatched wasp larva consumes the caterpillar.
E) A bluejay forces sparrows to leave a bird feeder so that it can eat the seeds.

Accepted Answer

In a mutualistic interaction, both species benefit. In this case, the bacterial species provides usable nitrogen to the plant, which benefits the plant by allowing it to grow more effectively. In turn, the plant provides sugar nutrients to the bacteria, which benefits the bacteria.