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.

advantage of using stem cells in medical research:

1.       it provides medical benefits in the fields of therapeutic cloning and regenerative medicine.

2. it provides great potential for discovering treatments and cures to a variety of diseases including parkinson disease, spinal cord injuries, diabetes, alzheimer’s disease and many more.

3. limbs and organ could be grown in lab from stem cells and then used in transplant or treat illness.

d. groundwater flows through the subsoil and deposits minerals.