Final answer:
The snake catching and swallowing frogs is an example of predation, not commensalism.
Step-by-step explanation:
Commensalism is a symbiotic relationship where one species benefits while the other is unaffected. In the case of a snake catching and swallowing frogs, it is not an example of commensalism. This relationship is an example of predation where the snake benefits by getting food, while the frog is harmed by being eaten.