The wombat, a meter-long herbivorous marsupial mammal found in Austral

Official Explanation

Analyze the information

Overall, things look bleak for the wombat. According to the stimulus, the only way to increase the wild wombat population is to reduce the human-created problems it faces, and those problems are increasing.

Approach strategically

For the first column, look for an answer choice describing a measure that would likely be effective in increasing wombat populations. The stimulus states that in order to be effective, measures taken must counteract human-created threats faced by wombats. Several choices describe such countermeasures, but only one doesn't appear to run the risk of harming wombats in the process: reducing the number of European rabbits in wombats' habitat through hunting. European rabbits are described as a threat to wombats introduced by humans, so reducing their numbers would help the wombat population, so this option is likely to be Effective. This is the correct answer for the first column.

On the other hand, introducing a feline predator that feeds only on mammals one meter in length or less is a terrible idea, even if doing so would reduce the rabbit population. Since wombats are mammals and they are one meter long, the feline predators would be likely to eat the wombats, too. Similarly, reducing the rabbit population with poison-laced food supplies would likely be harmful to wombats, since the wombats compete with rabbits for food and may be poisoned as well. These options would likely be ineffective at increasing the wombat population, but they're also harmful to wombats, so they're incorrect for both columns.

For the second column, look for an answer choice describing a measure unlikely to be increase wombat populations but also unlikely to be harmful. There are two choices left to look at. Converting several square miles of open grassland to fenced-in ranches to protect sheep from dingoes would, according to the stimulus, be harmful to wombats, as "habitat encroachment due to farming and ranching" is listed as a human-created threat to wombats. Also, one might logically reason that if sheep are harder for dingoes to catch, they may eat more wombats. The remaining choice, introducing wombats raised in captivity into habitats already containing wombats, must be the correct answer. Introducing new wombats isn't likely to be effective, according to the stimulus, because it doesn't counteract any human-made threats. But introducing new wombats isn't especially harmful, either, since it doesn't introduce any new threats. Therefore, it is likely to be Ineffective.

TAKEAWAY: Make sure you consider all criteria for each column; the right answer has to fit all of them.