Question

Agglutination occurs in the blood sample present in a test tube. This indicates
A) Antibodies are present in plasma
B) Antigens are present on red blood corpuscles
C) Antigens are present in plasma
D) Antibodies are present on red blood corpuscles

Answer 1

In the previous days, before the discovery of blood groups, whenever there is the transmission of blood takes place, doctors noticed that some people have agglutination of blood, so to know this lot of research was done by the scientist, later Karl Landsteiner is the Austrian scientist, who discovered the ABO blood groups where typing of blood is started to prevent the agglutination while transmission.

Complete answer:
Karl Landsteiner discovered the antigen and antibody for the blood groups and this led to the discovery of the ABO blood group system.
Antigens are A and B which are usually present on the surface of the RBC, and the name of the blood group is based on the type of antigen present in the blood.
And at the same time, persons have antibodies that are present in the plasma.
The classification of blood group is done as
A-- Antigen A, and Anti b antibody.
B--Antigen B, and Anti A antibody.
AB-- Antigen A, and B, and no antibodies.
O---They don’t have antigens but have both anti-A, and anti B antibodies in the plasma.
During blood transmission typing of blood is done, where the recipient blood is taken in the test tube and donor blood is added, if the antigen of the donor blood matches with antibodies of recipient blood then it results in agglutination.

So, the correct option is B.

Note: Agglutination means clumping of blood, it causes severe complications, so to prevent it typing of blood should be done, and this agglutination is mainly based on the type of antigen present on the blood, and the name of blood group also depends on the presence of a type of antigen on RBC.