Question

the walnut twig beetle is native to the southwestern united states and mexico. it is considered an invasive species in the western united states. this beetle can carry a fungus that causes thousand cankers disease in black walnut trees. thousand cankers disease can be lethal to trees after only a few years of infection.
in 2013, scientists discovered thousand cankers disease in black walnut trees in north carolina, in the great smoky mountains national park. these scientists hypothesized that the disease was transported to the area by humans. which of these statements best supports the scientists hypothesis?
the disease is caused by a fungus that is carried by a beetle.
black walnut trees are susceptible to thousand cankers disease.
people from north carolina visit the great smoky mountains national park every year.
walnut twig beetles were previously found only in the western and southwestern united states.

Explanation:

The hypothesis is that the disease was transported by humans. If walnut - twig beetles (which carry the disease - causing fungus) were previously found only in the western and southwestern United States, and then the disease was discovered in North Carolina (a new location), it implies that some external factor, likely human activity, could have moved the beetles (and thus the disease) to this new area. The other options do not directly support the human - transport hypothesis.

Answer:

Walnut twig beetles were previously found only in the western and southwestern United States.