Answer:
The absence of RH antígen on the red blood cells
Explanation:
The OAB blood group nomenclature includes the Rh system, important for blood transfusion, there are six types of Rh antigens, the D antigen is the most common in the population, which is why people who have it are called Rh positive and those without Rh negative, allowing specific applications.
Answer:
before eating is known as preprandial sample and
after eating is known as postprandial sample