Which statement supports the proposition that the presence of an X chromosome appears to be necessary for life?
A) X-chromosomal genotypes are expressed as consistent phenotypes at a rate of around 85%, while Y-chromosomal genotypes are expressed as consistent phenotypes at a rate of only about 15%.
B) The X chromosomes are expressed far earlier in the prenatal period than the Y chromosomes.
C) There are no chromosomal disorders wherein a person has only Y chromosomes.
D) Most of the lethal chromosomal disorders, including Tay-Sachs disease and cystic fibrosis, are located on the Y chromosome.

Question

Which statement supports the proposition that the presence of an X chromosome appears to be necessary for life?
A) ​X-chromosomal genotypes are expressed as consistent phenotypes at a rate of around 85%, while Y-chromosomal genotypes are expressed as consistent phenotypes at a rate of only about 15%.
B) ​The X chromosomes are expressed far earlier in the prenatal period than the Y chromosomes.
C) ​There are no chromosomal disorders wherein a person has only Y chromosomes.
D) ​Most of the lethal chromosomal disorders, including Tay-Sachs disease and cystic fibrosis, are located on the Y chromosome.

Quizplus · Accepted Answer

This statement supports the proposition that the presence of an X chromosome appears to be necessary for life because it highlights the fact that no chromosomal disorders are known to occur when a person has only Y chromosomes. This suggests that the X chromosome is necessary for life, as the absence of an X chromosome is not viable.

Which Statement Supports the Proposition That the Presence of an X