In humans, the allele for Rh factor comes in two forms: Rh+ and Rh–. Inheritance of the alleles determines whether an individual has either Rh+ blood or Rh– blood. To identify the dominant form of the allele, which of these questions is the MOST USEFUL to investigate?

A. Which of the two alleles is more common in the human population?

B. Which of the two blood types is more common in the human population?

C. Which blood type forms when an individual receives two copies of one of the alleles?

D. Which blood type forms when an individual receives one copy of each allele?

The correct answer is:

which of the blood type forms when an individual receives one copy of each allele? (D)

Explanation:

Alleles are each of the alternative forms of a gene. In this example, the two forms of the alleles for the Rhesus (Rh) factor are Rh+ and Rh-. These alleles can either be expressed as h0m0zygous alleles (two of the same kind; Rh+ Rh+, Rh- Rh-) or heterozygous alleles (a pair made up of both; Rh+ Rh-)

In the h0m0zygous state, there is the expression of the allele that makes up the pair. However, in the heterozygous state, the dominant allele is expressed phenotypically, even in the presence of the recessive allele that makes up the genotype. Therefore, the dominant allele is the resulting blood group seen in an individual in a heterozygous (one copy of each) state.

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%