Rohit, Rohan's elder brother, met with an accident on his way back from school and lost a significant amount of blood. At the hospital the doctor said he needed an immediate blood transfusion.
Rohan overheard the doctor asking about everyone's blood group in the family. Their father's blood group is O and their mother's blood group is AB. Based on the information given above, answer the questions that follow :

(a) Suppose Rohit's blood group is B. Which parent can give blood to him - his mother or his father ?

(b) If Rohan's blood group is A, can he donate blood to his brother ?

(c) Blood groups are said to be differentiated based on the presence of certain antigens. What are antigens and where are they found in the blood ?

(a) If Rohit’s blood group is B, then he can receive blood from B and O groups. His father has blood group O, so he can donate blood to Rohit. His mother (AB) cannot donate to B group because mother with AB blood group has both A and B antigens on the surface of their red blood cells.

(b) If Rohan’s blood group is A, Rohan cannot donate blood to his brother because blood group A cannot donate to B, because of incompatibility of antigens and antibodies.

(c) Antigens are special proteins present on the surface of red blood cells (RBCs). They determine a person’s blood group (A, B, AB, or O).