According to the ABO system , the commonest blood group in the human population is (X) while the rarest blood group is (Y) . If the wife has (X) blood group and the husband has (Y) blood group , their children will have which of the following blood groups ?

Options

A. AB and O groups only
B. AB only
C. A and B groups only
D. All four groups

Answer

To solve the question regarding the blood groups of the children based on the ABO system, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Blood Groups**:
- The commonest blood group (X) is O blood group, which is represented by the genotype (ii).
- The rarest blood group (Y) is AB blood group, which is represented by the genotype (IAIB).

2. **Determine the Genotypes of the Parents**:
- The wife has blood group O, so her genotype is (ii).
- The husband has blood group AB, so his genotype is (IAIB).

3. **Set Up a Punnett Square**:
- To find the possible blood groups of their children, we can set up a Punnett square using the genotypes of the parents.
- The alleles from the wife (ii) can only contribute (i) to the offspring.
- The alleles from the husband (IAIB) can contribute either (IA) or (IB).

4. **Fill in the Punnett Square**:
- The Punnett square will look like this:

```
IA IB
----------------
i | IAi | IBi |
----------------
i | IAi | IBi |
----------------
```

5. **Determine the Blood Groups of the Offspring**:
- From the Punnett square, we see that the possible genotypes for the children are:
- IAi (which corresponds to blood group A)
- IBi (which corresponds to blood group B)

6. **Conclusion**:
- Therefore, the children can have either blood group A or blood group B.

### Final Answer:
The children will have blood groups A and B.

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