1. how did avery, macleod, and mccarty contribute to our understanding of dna? a. used x ray diffusion to examine the structure of dna b. determined that dna contains four different nitrogenous bases c. found that the "transforming principle" is destroyed by enzymes that hydrolyze dna d. found that the phosphorus-containing components are the genetic material of phages e. discovered "the transforming principle" that could genetically alter bacteria

The correct answer is E. Discovered "the transforming principle" that could genetically alter bacteria.

Explanation:

Oswald Avery, Colin MacLeod and Maclynn McCarty experimented with pneumococcus and suggested that DNA (rather than protein as believed at the time) may be the hereditary material of bacteria, and could be analogous to genes in higher complexity organisms.

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.