Final answer:
Protecting a newly discovered rat species would most effectively be done by stopping habitat loss, as it supports the species' survival directly by maintaining their natural environment, which is necessary for their overall health and longevity. The correct answer is b. Habitat loss.
Step-by-step explanation:
Stopping habitat loss would likely help protect a newly discovered rat species the most. Habitat loss often leads to decreased biodiversity, as it can result in the destruction of the specific environment the species requires to survive. For example, the declining biodiversity of the fauna and flora of Alpine and Mediterranean regions and the decline of certain species in Britain due to aggressive use of rat poisons, emphasize the importance of habitats for species survival. Furthermore, historical outbreaks of plague in Europe related to rodents demonstrate the interconnection between the health of animal populations and their habitats.
While legal hunting, poaching, and the spread of plague can be significant threats to a species, the loss of habitat can fundamentally undermine the ability of species to maintain viable populations. Moreover, a species may still produce compounds or possess behaviors that can help protect against predation or disease, but without a suitable habitat, these defenses are moot as the species cannot thrive.