Final answer:
The allele HbS codes for the type of hemoglobin associated with sickle-cell anemia, which is a harmful autosomal recessive. It is caused by a mutation in the normal allele HbA for hemoglobin. Sickle cell anemia is characterized by red blood cells taking on a sickle or crescent shape, disrupting capillary flow and oxygen delivery.
Step-by-step explanation:
The allele HbS that codes for the type of hemoglobin associated with sickle-cell anemia is a harmful autosomal recessive. It is caused by a mutation in the normal allele HbA for hemoglobin, which is a protein on red blood cells. Sickle cell anemia is characterized by red blood cells taking on a sickle or crescent shape, disrupting capillary flow and oxygen delivery.