7. In some chickens, the gene for feather color is controlled by codominance. The allele for black is B and the allele for white is W. The heterozygous phenotype is known as erminette.

a. What is the genotype for black chickens?

b. What is the genotype for white chickens?

c. What is the genotype for erminette chickens?

d. If two erminette chickens were crossed, what is the probability that:

i. They would have a black chick? %

ii. They would have a white chick? % iä. They would have an erminette chick? %

See the answer below

Explanation:

Genotype is the genetic composition of organisms and a gene is made up of two alleles.

a) Since the allele for black is B, the genotype for black chickens would be BB.

b) Since the allele for white is W, the genotype for white chickens would be WW.

c) Since erminette color is heterozygous, the genotype would be BW.

d) Two erminette were crossed:

         BW    x    BW

      BB BW BW WW

i. Probability of having black chick (BB) = 1/4

ii. Probability of having a white chick (WW) = 1/4

iii. Probability of having erminette chicken (BW) = 1/2

the law of original horizontality explains:   why rocks appear in layers. correct answer: b the law suggests that all rock layers are originally laid down (deposited) horizontally and can later be deformed.   the principle is used by geologists to make assumptions about the relative ages of sedimentary rocks.