The answer you are looking for is:<span>capillary beds</span>
A sudden shift in the tectonic plates of the earth
The answer is most likely B). 'The harmless bacteria would not have been transformed, and the mice would have lived,' because, then bacterium transform, they use the genetic material present in their environment to do so, and when Avery destroyed the nucleotide bases(Genetic material) with an enzyme he destroyed any chances that the bacteria would have had at transforming into the virulent strain.
