Answer:
Option C
Explanation:
Dr. Leland Hartwell used baker’s yeast, Saccharomyces cerevisiae, as a model system, which was a highly suitable model for cell cycle studies. He introduced the concept of Checkpoints where he said cells are arrested if damaged so that the cells repair system can work to correct such damages. Dr. Paul Nurse used a different type of yeast, Schizosaccharomyces pombe, a type of yeast distantly related to the baker's yeast as a model organism.
