Which of the following statement is NOT true of therapeutic cloning a. "Therapeutic" cloning is used mainly for research purposes and therefore should be allowed to continue. b. "Therapeutic" cloning is used for medical purposes and not for reproducing full human beings. c. "Therapeutic" cloning is used for replacing the diseased parts of human organs. d. Brain cell can be used in the future to cure the Parkinson’s disease.

在乳糖操纵子中，阻遏蛋白识别操纵子的是

A．I基因
B．O序列
C．P序列
D．Y基因
E．Z基因