The condition characterized by a lack of melanin in skin, hair, and eyes is: MCQ with Answer and Explanation

Explanation:
Bacterial cell walls contain peptidoglycan (murein), a unique polymer that maintains cell shape and protects against osmotic pressure. The reason correctly explains why peptidoglycan is essential.

Explanation:
Codominance occurs when two different alleles of a gene are fully and equally expressed in the heterozygous condition. In the ABO blood group, the IA and IB alleles are codominant. An individual with the genotype IAIB produces both A and B antigens on the surface of their red blood cells, resulting in the AB blood type. While the ABO system also involves multiple alleles (IA, IB, i), the specific expression of both antigens is codominance.

Explanation:
Hemophilia A and B are X-linked recessive disorders caused by mutations in genes for clotting factor VIII or IX on the X chromosome. It predominantly affects males, while females are usually carriers. Down syndrome is an autosomal aneuploidy, cystic fibrosis and sickle cell anemia are autosomal recessive. X-linked disorders follow a characteristic pattern of inheritance.