The R.B.C's have ........ types of sugars.

Options

A. One
B. Two
C. Three
D. Four

Explanation

To solve the question regarding the types of sugars present on the surface of Red Blood Cells (RBCs), we can follow these steps:

### Step-by-Step Solution:

1. **Understanding RBCs and Blood Groups**:
- Red Blood Cells (RBCs) have specific antigens on their surface, which are responsible for determining blood types. The main blood group system is the ABO blood group system.

2. **Identifying the Alleles**:
- The ABO blood group system is determined by three alleles: IA, IB, and i.
- The IA allele produces antigen A, the IB allele produces antigen B, and the i allele does not produce any antigen.

3. **Co-dominance Phenomenon**:
- When both IA and IB alleles are present in an individual (genotype IAIB), both antigens A and B are expressed on the RBC surface. This is known as co-dominance, where both alleles contribute equally to the phenotype.

4. **Types of Sugars**:
- The presence of these antigens corresponds to specific types of sugars:
- Antigen A corresponds to sugar A.
- Antigen B corresponds to sugar B.
- Type O (genotype ii) has no antigens, hence no sugars.
- Type AB (genotype IAIB) has both sugars A and B.

5. **Conclusion**:
- Therefore, RBCs can have two types of sugars: A and B, depending on the blood group. The correct answer to the question is **2 types of sugars**.

### Final Answer:
The RBCs have **2 types of sugars**.

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