Final answer:
Cannibalism in cane toad tadpoles is an example of selfishness (option 2), reflecting a survival strategy that involves intraspecific competition and plays a role in population control of the species.
Step-by-step explanation:
Cannibalism in cane toad tadpoles is an example of selfishness. This behavior occurs because it provides a survival advantage to the tadpoles that eat conspecifics (e.g., eggs or other tadpoles), allowing them better access to resources, enhanced growth, and increased chances of reaching adulthood. The phenomenon plays a role in the intraspecific competition within cane toad populations, helping in population control but also potentially slowing down the spread of this invasive species in Australia by suppressing the tadpole's growth and survival when exposed to chemical signals from conspecifics.