The sex of birds, some insects, and other organisms is deter…

The sex of birds, some insects, and other organisms is determined by a ZW chromosomal arrangement in which the males have like sex chromosomes (ZZ) and females are ZW. Assume that a recessive lethal allele on the Z chromosome causes death of an embryo in birds. What sex ratio would result in the SURVIVING offspring if a cross were made between a male heterozygous for the lethal allele and a normal female?