Genes or alleles which can express independently when they are present together and also follow the law of segregation are -

Options

A. Multiple genes
B. Codominant genes
C. Epistatic genes
D. Complementary genes

Answer

To solve the question regarding genes or alleles that can express independently when present together and also follow the law of segregation, we can break it down step by step:

### Step-by-Step Solution:

1. **Understanding the Terms**:
- First, we need to clarify what is meant by "genes or alleles that express independently." This refers to alleles that do not influence each other's expression when they are present together.
- The "law of segregation" states that during the formation of gametes, the alleles for a trait segregate from each other so that each gamete carries only one allele for each gene.

2. **Identifying the Type of Genes**:
- We are looking for a type of gene that allows for independent expression and adheres to the law of segregation.
- In genetics, this is typically seen in multiple alleles or co-dominant alleles where both alleles can be expressed simultaneously.

3. **Examples of Gene Expression**:
- A classic example is the ABO blood group system, where alleles I^A and I^B are both dominant and can express together in the presence of each other (resulting in type AB blood).
- This demonstrates that both alleles can be expressed independently of one another.

4. **Conclusion**:
- Based on the definitions and examples, the correct answer to the question is "multiple genes." These genes can express independently and follow the law of segregation.

### Final Answer:
The correct answer is **multiple genes**.