In birds, sex is determined by a ZW chromosome scheme. Males are ZZ and females are ZW. A recessive lethal allele that causes death of the embryo is sometimes present on the Z chromosome in pigeons. What would be the sex ratio in the offspring of a cross between a male that is heterozygous for the lethal allele and a normal female?

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#Question id: 12579

#XL - R Botany

Which of the following probably contains the highest concentration of toxic pollutants (biological magnification)? 

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#Question id: 11763

#XL - S Microbiology

What makes certain red algae appear red?

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#Question id: 20086

#XL - P Chemistry

On which factor van-der waalls attraction force does not depend ?

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#Question id: 5537

#XL - T Zoology

The segmented blocks of tissue that develop on each side of the notochord are called the

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#Question id: 3484

#XL - T Zoology

Modern behavioral concepts relate the cost of a behavior to its benefit. Under which relationship might a behavior be performed?

A) cost is greater than the benefit

B) cost is less than the benefit

C) cost is equal to the benefit