Different forms of a gene are called

Options

A. Heterozygotes
B. Alleles
C. Complementary genes
D. Supplementary genes.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the term that describes different forms of a gene.

2. **Identifying the Options**: The options provided are:
- Heterozygotes
- Alleles
- Complementary genes
- Supplementary genes

3. **Defining the Terms**:
- **Heterozygotes**: These are individuals that have two different alleles for a particular gene. They do not refer to the forms of the gene itself.
- **Alleles**: These are different forms of a gene that occur at the same locus on homologous chromosomes. For example, the A, B, and O blood group genes are all alleles of the same gene.
- **Complementary genes**: These are genes that work together to produce a single characteristic, but they can mask each other's effects.
- **Supplementary genes**: These are genes that also contribute to a single characteristic, where one gene can mask the effect of another.

4. **Choosing the Correct Answer**: Based on the definitions, the term that refers to different forms of a gene is **alleles**.

5. **Final Answer**: Therefore, the correct answer to the question is **alleles**.

---