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Correct Answer: positive rh factor.
the rh factor, short for rhesus factor, is a protein that can be present on the surface of red blood cells. this protein is what determines whether the blood type of an individual is positive or negative. the presence of the rh factor protein is indicated as positive (+), while its absence is marked as negative (-).
the inheritance of the rh factor follows a simple mendelian trait, where the rh-positive allele (r) is dominant over the rh-negative allele (r). this means that the genotype of an individual can be either rr (homozygous positive), rr (heterozygous positive), or rr (homozygous negative).
in the scenario provided in the question, a child receives one positive rh factor gene and one negative rh factor gene from their parents. this child's genotype would be rr. due to the dominance of the rh-positive allele, having even one copy of the positive allele (r) is enough to express the rh-positive phenotype. consequently, the child will display a positive rh factor in their blood type.
thus, when a child inherits one negative (r) and one positive (r) rh factor gene, the phenotype will be rh-positive. this is because the presence of the dominant rh-positive allele masks the effect of the recessive rh-negative allele. therefore, the correct answer to the question is:
"positive rh factor."
this understanding is crucial for various medical scenarios, including blood transfusions and pregnancy, where rh compatibility plays a significant role in preventing complications. knowing the rh factor helps manage rh incompatibility, particularly in pregnancies where the mother is rh-negative and the child is rh-positive, which can lead to rh disease of the newborn if not properly managed.
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