Barred feather pattern is a z-linked dominant trait in chickens. what offspring would you expect from (a) the cross of a barred hen to a non-barred rooster? (b) the cross of an fl rooster from part (a) to one of his sisters?

Let the "barred" allele be caller B and the "non-white" allele b. Since chickens use chromosomes  and to determine sex, hens would have chromosomes , and roosters would have chromosomes . A Z-linked gene is represented as a superscript on the chromosome, for the dominant allele and for the ressesive allele.

A barred hen would have a copy of B on its Z chromosome, a non-barred rooster would have both copies of b on both Z chromosomes. Using Punnet squares to represent the crosses we get the following cases:

That is a ratio of two barred heterozygote roosters to two non-barred hens. Crossing them we get:

That is a ratio of one barred heterozygote rooster to one barred hen to one non-barred rooster to one non barred hen.

estuaries are the partially enclosed coastal bodies of brackish water formed at the mouth of sea where river meets an ocean. it is a transition zone between river and sea water so estuaries are influenced to both marine environment such as tides, waves and to riverine such as flow of fresh water and sediments. the mixing of sea and fresh water provide high level of nutrients, making estuaries a high product habitats.

many estuaries suffers degradation from a variety of human activities like erosion from deforestation, overgrazing, overfishing, drainage and eutrophication.

so from the above statement answers will be

1. false as estuaries are formed due to both brackish and freshwater.

2.true, due to high productivity estuaries are breeding ground for many marine species.

3. direct and indirect activities of man that contribute to pollution and deposition of sediments.