The prion-induced disease Bovine Spongiform Encephalopathy (BE - also known as mad-cow disease) causes severe degeneration of neural tissue resulting ultimately in death. The incubation period for this disease is very long in humans (many years), and the length of the incubation period is in part thought to be determined by genetic factors. Katerina Manalakou and colleagues (Manalakou et al. 2001) sought to investigate whether incubation period for BS varied in two genetic strains of mice (the C57BL and RIll strains) that were experimentally infected with BSE. They counted the number of days between infection and onset of first symptoms of BSE this being the incubation period.

1. Are one, or two populations being sampled here?

A. 1

B. 2

2. Name the population(s) being sampled?

Select one:

A. all mice

B. Mice from the C57BL strain and mice from the RIll strain