If a healthy cell passes the G1/S checkpoint（）
A. DNA will be replicated
B. it will enter the G0 stage of the cell cycle
C. it will not divide
D. it will proceed immediately to cytokinesis
E. it will die
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In poodles, black is dominant to white. A black poodle is crossed with a white poodle. In a litter of four, all of the puppies are black. What is the best conclusion（）
A. The black poodle is probably homozygous
B. The black poodle is definitely homozygous
C. The black poodle is definitely heterozygous
D. The black poodle is probably heterozygous
What process is unique to plants（）
A. double fertilization
B. meiosis
C. crossing ove
D. haploid gametes
E. spermatogenesis
In order to be functional, a eukaryotic chromosome requires all of the following except（）
A. a nucleoid.
B. a centromere
C. origins of replication
D. telomeres
Which of the following scientists contributed significantly to the foundations of transmission genetics（）
A. Thomas Hunt Morgan
B. James Watson
C. John B. S. Haldane
D. Charles Darwin
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