Which of the following is an example of mutualism? A. Twisting about like a high-flying acrobat, the gray flycatcher plucks moths from the air.
B. On the bird feeders of many residents of southern Illinois, people can watch the fox squirrels and gray squirrels fight with each other for the bird seed, while the birds get scared away by the activity!
C. Scratching with great vigor, the chipmunk tried to knock loose the tick stuck firmly to its ear.
D. Some biologists have observed Egyptian Plovers, a type of bird, land on the open mouth of a Nile crocodile without being eaten and remove leeches stuck firmly to the crocodile's gums.

D. Some biologists have observed Egyptian Plovers, a type of bird, land on the open mouth of a Nile crocodile without being eaten and remove leeches stuck firmly to the crocodile's gums.

Explanation:

Mutualism is when two animals are together and they are benefitted and nobody gets harmed. In this situation, the bird and the crocodile aren't attacking each other but they are both helping each other. The bid gets a nice meal and th crocodile can get rid of those leeches. In the other situations there are teo creatures but one ends up getting eaten and that is not what mutualism is about.

not sure if this is what you'r looking for eubacteria and archaebacteria