Lethal genes (genes that result in the failure to develop a vital organ or metabolic pathway)are nearly always recessive.Animal breeders who discover a unique trait and selectively breed to increase the occurrence of that trait often encounter a noticeable increase in lethal genes.Why?

A)The lethal recessive gene may be incompletely dominant.
B)Spreading the gene among offspring of both sexes will increase the likelihood it will be sex-linked and expressed.
C)The selective-mating of closely related individuals,or inbreeding,increases the chances that two recessive genes will "meet" in offspring.
D)"Pleiotropy"-the gene that is being selected for this trait may have the second effect of being lethal.
E)"Epistasis"-selection for the desired trait may result in "uncovering" the lethal gene.