Dr. Alan Hicks entered a cave and noted thousands of dying and dead bats. Surprisingly, they all had white fungal growth on their noses (white-nose syndrome or WNS). This same phenomenon was observed in many caves. This repeated observation of an occurrence in the natural world is called a(n) . Dr. Hicks contacted other scientists, and together they set out to determine what was causing the white noses on the bats, for they suspected that it was leading to the bat deaths. This potential explanation is termed a(n) . Several different types of experiments were set up to test the idea that the fungus was leading to death in the bats. Eventually, it was determined that contact with Pseudogymnoascus destructans does lead to sickness and death in bats. The repeated testing of this idea, along with other scientific knowledge, allowed the scientists to develop the that Pseudogymnoascus destructans causes WNS, which leads to the eventual death of the bats.