Allele is the :-

Options

A. Alternative from of gene pair
B. Total number of genes for a trait
C. Total number of chromosomes of a haploid set
D. Total number of genes present on a chromosome

Answer

To answer the question "Allele is the:", we will analyze the options provided and determine the correct definition of an allele.

### Step-by-Step Solution:

1. **Understand the Definition of an Allele**:
- An allele is a variant form of a gene. While genes are segments of DNA that code for specific traits, alleles are different versions of these genes that may produce variations in the traits.

2. **Analyze the Options**:
- **Option 1**: Alternative form of gene pair.
- **Option 2**: Total number of genes for a trait.
- **Option 3**: Total number of chromosomes of a haploid set.
- **Option 4**: Total number of genes present on a chromosome.

3. **Evaluate Each Option**:
- **Option 1**: This correctly describes alleles as they are indeed alternative forms of a gene pair (e.g., one allele for brown eyes and another for blue eyes).
- **Option 2**: This refers to the total number of genes for a trait, which does not define an allele.
- **Option 3**: This option discusses chromosomes, which is unrelated to the definition of an allele.
- **Option 4**: This option talks about the total number of genes on a chromosome, which is also not the definition of an allele.

4. **Select the Correct Answer**:
- Based on the analysis, **Option 1**: "Alternative form of gene pair" is the correct answer.

### Final Answer:
Allele is the alternative form of a gene pair.