In heterozygous condition, both the alleles express in

Options

A. Colour blindness
B. AB blood group
C. Rh factor
D. A and B blood types

Answer

### Step-by-Step Solution:

1. **Understand Heterozygous Condition**:
- A heterozygous condition occurs when an organism has two different alleles for a particular gene. For example, if one allele is for brown eyes (B) and the other is for blue eyes (b), the organism is heterozygous (Bb).

2. **Evaluate the Options**:
- **Option 1: Colorblindness**: This condition is typically caused by a recessive allele. In a heterozygous individual (XcX), only the dominant allele is expressed, meaning that colorblindness does not express both alleles simultaneously. Thus, this option is incorrect.

- **Option 2: AB Blood Group**: In this case, both A and B alleles are present and expressed. This is an example of co-dominance, where both alleles contribute to the phenotype. Therefore, this option is correct.

- **Option 3: Rh Factor**: The Rh factor also follows a pattern where the presence of the dominant allele determines the phenotype. In a heterozygous condition (Rh+Rh-), only the dominant Rh+ allele is expressed, making this option incorrect.

- **Option 4: A and B Blood Types**: Similar to the Rh factor, if an individual has one A allele and one B allele, only one type will be expressed at a time unless both are present, which is not the case here. Thus, this option is also incorrect.

3. **Conclusion**:
- After evaluating all the options, the only situation where both alleles express themselves in a heterozygous condition is in the AB blood group (Option 2). Therefore, the correct answer is Option 2.

### Final Answer:
**Option 2: AB Blood Group** is the correct answer, as it demonstrates co-dominance where both alleles are expressed.