You have isolated a soil protozoan, which you are now trying to grow in pure culture. you have tried many different types of media but find you can only grow the protozoan if bacteria are also present in the medium. you note that the bacterial population declines as the protozoan population increases. based on this evidence, which of the following types of symbiotic relationships do you suspect might be occurring between the protozoan and the bacteria?
a. ammensalistic
b. commensalistic
c. mutualistic
d. predatation