Introduction:
In a population, there can be multiple alleles for a specific gene. These multiple alleles arise due to genetic variations and mutations. However, individuals within the population can only have two of those alleles. This is because of the concept of diploidy and the presence of homologous pairs of chromosomes in most organisms.

Diploidy and Homologous Pairs of Chromosomes:
Diploidy refers to the presence of two sets of chromosomes in an organism, one inherited from each parent. In most organisms, including humans, the chromosomes are present in homologous pairs. Each homologous pair contains one chromosome from each parent, carrying different versions of the genes. These different versions are the multiple alleles.

Mendelian Inheritance:
According to Mendelian inheritance, an individual inherits one allele from each parent for a specific gene. During gamete formation, the homologous chromosomes separate, and each gamete receives only one of the two alleles. When fertilization occurs, each parent contributes one allele, resulting in the offspring having two alleles for each gene.

Genotype and Phenotype:
The combination of alleles an individual possesses is called the genotype. The genotype determines the phenotype, which is the physical expression or traits exhibited by an organism. For most genes, such as eye color or blood type, there are multiple alleles present in the population. However, each individual can only carry two alleles, one from each parent.

Allele Frequencies and Population Genetics:
The presence of multiple alleles within a population contributes to genetic diversity. The frequency of each allele in a population can vary, and this variation is important in population genetics and evolution. Factors such as natural selection, genetic drift, and gene flow influence the distribution of alleles within a population over time.

Conclusion:
In summary, a population may have multiple alleles for a specific gene due to genetic variations and mutations. However, individuals can only have two of those alleles, one inherited from each parent. This is due to the concept of diploidy and the presence of homologous pairs of chromosomes in most organisms. The presence of multiple alleles within a population contributes to genetic diversity and plays a crucial role in population genetics and evolution.