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.

step 1 ammonium can be absorbed by plants, but some is converted into nitrates which are better for plants to absorb. this is called nitrification. 2. step 2 the deer eats the plants and uses the nitrogen-containing proteins for cell growth. 3. step 3 bacteria in the soil conduct nitrogen fixation to convert nitrogen gas from the atmosphere into ammonium. 4. step 4 some of the nitrates are absorbed back into plants, but denitrification breaks down the nitrates into nitrogen gas released back into the atmosphere. 5. step 5 nitrogen is found in the urine, which gets broken down into ammonium through the process of ammonification. 6. step 6 plants absorb the ammonium and begin assimilation, the process to add the nitrogen to protein.