Which of the following is an example of an invasive species on the island of Guam?

The brown tree snake is a well-documented invasive species on the island of Guam. Originally from New Guinea and the Solomon Islands, this snake was accidentally introduced to Guam after World War II. Its presence has had devastating effects on the native wildlife; it has played a significant role in the decline and extinction of several bird species endemic to the island. The brown tree snake’s ability to reproduce quickly and adapt to the local environment has enabled it to thrive, further exacerbating the ecological impacts on Guam's biodiversity.

In contrast, while the other species listed may also be considered invasive in different contexts or regions, they do not have the same historical or ecological significance within the ecological narrative of Guam. The green iguana, for example, is indeed an invasive species in some areas, but it does not have the same level of impact on Guam's native ecosystem as the brown tree snake. Similarly, the Burmese python and common carp are invasive in other environments, but their effects are not as pronounced on Guam’s specifically unique ecosystems as the brown tree snake has been.