I think its a deeper current probably..
I hope this helps<span />
Answer: I think its centriole
A marked change in the environment favors some characteristics of plants, animals and microbes over others. These character differences are often genetically based so that favored characteristics may increase in the next generation. The shorter the generation time, the faster this evolutionary change can occur.
Answer:
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.
I think so and viruses can have a disease that can kill you