Which example illustrates commensalism and NOT mutualism?
A
Hippo dung is eaten by a large species of catfish native to African lakes. The catfish typically follow the hippo herds.
B
Cattle have protozoa living in their gut that digest cellulose. The cows are able to feed on grass, while the protozoa are sheltered inside the cow.
C
Oxpeckers remove parasitic fly larvae from the skin of buffalo. In exchange, they are protected from predatory cats, who will not challenge a buffalo.
D
Ants 'farm' aphid insects like cattle. Aphids suck the sap out of trees, which ants also feed on. In turn, the ants sting predators that attack the aphids.