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What cannot be true for a man having a B+ve blood group?

Correct answer: D. His father's blood group is AA

  • A. His mother's blood group is BB
  • B. His mother's blood group is BO
  • C. His father's blood group is AO
  • D. His father's blood group is AA

Explanation

If a man has a B+ (B positive) blood group, the following statements cannot be true: 1. He has an O- (O negative) blood group: Blood group O- is different from B+ as it lacks both A and B antigens on red blood cells and has Rh-negative factor. A person cannot simultaneously have two different blood types. 2. He can receive blood from AB+ (AB positive) donors: B+ individuals can only receive blood from compatible donors with B positive, B negative, O positive, or O negative blood types. AB+ blood contains the A antigen, which is incompatible with B+ blood. 3. He has both A and B antigens on his red blood cells: B+ blood type indicates the presence of B antigen on red blood cells but not A antigen. A person cannot have both A and B antigens simultaneously. 4. He can donate blood to individuals with AB- (AB negative) blood group: B+ individuals can donate blood to those with B positive, B negative, AB positive, AB negative, O positive, or O negative blood groups. However, they cannot donate to individuals with AB- blood type as it lacks the Rh factor present in B+ blood. 5. He can pass on the O antigen to his offspring: If a man has a B+ blood group, he carries the B antigen and not the O antigen. The O antigen is present in individuals with blood group O. Therefore, he cannot pass on the O antigen to his biological children. Remember that blood types follow specific genetic patterns, and certain combinations are not possible.

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Mendel's laws explain segregation, independent assortment and the prediction of genetic ratios using alleles, genotypes and phenotypes. The chapter also covers linked genes, recombination and crossing over during meiosis, then applies pedigree reasoning to X-linked recessive traits, which show different inheritance patterns in males and females.

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