Lyme disease, like many other zoonotic diseases, is transmitted by insects that carry pathogens by ingesting blood from vertebrate hosts. Scientists have long believed that the population density of white-footed deer is the cause of Lyme disease The best predictors of rate. However, a 13-year study of the determinants of Lyme disease ecology in a high Lyme disease prevalence area in southeast New York overturned this view because in Lai In years with a high incidence of Lyme disease, the population of white-footed deer is generally lower than in years with a low incidence of Lyme disease. The above discussion is based on which of the following assumptions? ['Areas where there has never been an outbreak of Lyme disease.', 'White-footed deer population will not decrease significantly before Lyme disease outbreak.', 'Population numbers of other species can also be used as predictors of the onset of Lyme disease.', 'The increased population of white foot disease is a precursor to other disease outbreaks.']