The following are multiple choice questions (with answers) about medical knowledge.   **Question:** An investigator is studying the effect of drug X on the retinoblastoma (Rb) gene on chromosome 13 in endometrial cells. Endometrial cells obtained from study participants are plated on growth media and the distribution of cell cycle phase is measured with flow cytometry. Drug X, which is known to activate cyclin-dependent kinase 4, is administered to all the cells, and the distribution of cell cycle phase is measured again 1 hour later. Which of the following is most likely to result from the action of drug X on the Rb gene?   (A) G1 phase arrest   (B) Prophase I arrest   (C) Initiation of S phase   (D) Completion of G2 phase
['(C) Initiation of S phase <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) G1 phase arrest \n (B) Prophase I arrest \n (C) Initiation of S phase \n (D) Completion of G2 phase <> possible answers', '  An investigator is studying the effect of drug X on the retinoblastoma (Rb) gene on chromosome 13 in endometrial cells. Endometrial cells obtained from study participants are plated on growth media and the distribution of cell cycle phase is measured with flow cytometry. Drug X, which is known to activate cyclin-dependent kinase 4, is administered to all the cells, and the distribution of cell cycle phase is measured again 1 hour later. Which of the following is most likely to result from the action of drug X on the Rb gene? <> context@']