The Reason That Missing an X Chromosome and Having an Extra

Multiple Choice

The reason that missing an X chromosome and having an extra X chromosome do NOT cause more harm than they do is best explained by the

A) inactivation of any X beyond the first as a Barr body.
B) presence of genes on the Y chromosome that determine maleness.
C) presence of genes on the X chromosomes that determine femaleness.
D) loss of a sex chromosome in normal cells as embryo development occurs.
E) a higher level of gene-repair enzyme activity on sex chromosomes.