The surfaces of erythrocytes contain genetically determined types of proteins that are responsible for the two major blood group classifications, which are

Options

A. ABO and Rh
B. Type A and Type B
C. Type AB and O
D. `Rh^(-)andRh^(+)`

Answer

To answer the question regarding the two major blood group classifications based on the genetically determined proteins on the surfaces of erythrocytes, we can break down the solution into the following steps:

### Step-by-Step Solution:

1. **Understanding Blood Groups**: Blood groups are classified based on the presence or absence of specific antigens on the surface of red blood cells (erythrocytes). These antigens are proteins that are genetically determined.

2. **ABO Blood Group System**: The first major classification is the ABO blood group system. This system categorizes blood into four main types: A, B, AB, and O.
- Type A has A antigens on the surface of the erythrocytes.
- Type B has B antigens.
- Type AB has both A and B antigens.
- Type O has neither A nor B antigens.

3. **Rh Factor**: The second major classification is based on the Rh factor, which is another antigen that can be present or absent on the erythrocytes.
- If the Rh antigen (also known as the D antigen) is present, the blood group is classified as Rh positive (+).
- If the Rh antigen is absent, the blood group is classified as Rh negative (−).

4. **Combining Classifications**: Therefore, when combining the ABO system with the Rh factor, we can have eight possible blood group classifications: A+, A−, B+, B−, AB+, AB−, O+, and O−.

### Final Answer:
The two major blood group classifications are:
1. **ABO Blood Group System**
2. **Rh Factor (Rhesus Factor)**

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