Question

Parents have blood groups $A$ and $B$. Blood group of the child can be
(A) $A$ or $B$
(B) $O$
(C) $AB$
(D) All the above

Answer 1

Blood group in the body can be found by testing whether the particular antigens are present in the body or not. Antigens is defined as the substance that induces or triggers the body immune system if any foreign substance enter in to the body

Complete answer:
If the mother have the blood group $A$ and the father have the blood group $B$ or is the father have the blood of the type $A$ and the mother with the type $B$, then the child born to them will have either $A$ or $B$ or $AB$. Since $O$ is the common universal blood group, the child can also have this blood group. Hence all the given options are correct.
i) Blood group $A$: This blood has the antigen of the type $A$ and antibody of the type $B$.
ii) Blood group $B$: This blood has the antigen of the type $B$ and antibody of the type $A$.
iii) Blood group $AB$: This blood has the antigen of the type $A$ and $B$ and has no antibodies.
iv) Blood group $O$: This blood has no antigen and has antibodies of the type $A$ and $B$.

Thus the correct answer is option ‘D’,.

Note: Blood transfusion must be done very carefully. This is because the small change in the blood may lead to death. If the blood transfused does not match with the blood already present in the body, then the antigen present in the body triggers the antibody to kill the foreign blood antigens and this leads to death.