Dr. Smith has used the same strain of Salmonella for Gram staining in her teaching labs that she has cultured continuously 20 years. In her first year of teaching, a student accidentally ingested the Salmonella strain and became very ill. Twenty years later, a student spilled some Salmonella onto her pen and then put the pen into her mouth. Shockingly the student suffered no ill effects from ingesting the culture of Salmonella. Why did this occur

Astudent sees several ants walking up a wall following the exact same trail that an ant took earlier. she wants to apply the scientific method to determine how the ants detected the trail. which of these steps would come first in her application of the scientific method? perform an experiment by cleaning the scent away from part of the trail. draw a conclusion that the ants follow a scent trail. make a prediction about what the ants will do after she cleans away part of the trail. hypothesize that the ants are following a scent trail that the first ant left.