胆固醇合成的直接原料是
A.氨基酸B.乙酰CoAC.丙酮酸D.三酰甘油E.甘油
参考答案:B
牵牛花的红花基因(R)对白花基因(r)显性,阔叶基因(B)对窄叶基因(b)显性,它们不在一对同源染色体上,将红花窄叶纯系植株与白花阔叶纯系植株杂交,F1植株再与“某植株”杂交,它们的后代中:红花阔叶、红花窄叶、白花阔叶、白花窄叶的植株数分别是354、112、341、108,“某植株”的基因型为 [ ]
A.RrBb
B.Rrbb
C.rrBb
D.RRbb
— Can I use the telephone on the table, sir?
一 Under no circumstances ____to use the telephone in the office for personal affairs.
A.anyone is allowed
B.nobody is allowed
C.is anyone allowed
D.is nobody allowed