Assertion: Blood of group 'O' has Anti-A and Anti-B antibodies.
Reason: It does not have any antigens.
Both assertion and the reason are true and the reason is the correct explanation of the assertion.
Blood group A contains antigen A and antibody B
Blood group B contains antigen B and antibody A
Blood group AB contains both the antigens A and B, but no antibody.
Blood group O contains no antigen but has both the antibodies A and B