What alternate form of genes do nucleic acids have that allows them to offer variability?

The alternate forms of genes that nucleic acids can have, which allow for variability, are known as alleles. Alleles are different versions of the same gene that can arise through mutations or changes in the DNA sequence. These variations can result in different traits or phenotypes in an organism.

In diploid organisms, such as humans, alleles come in pairs, with one allele inherited from each parent. The combination of these alleles can influence various characteristics, such as eye color, hair type, and susceptibility to diseases.

Additionally, the variability introduced by different alleles contributes to the genetic diversity within populations, which is essential for evolution and adaptation to changing environments. For instance, certain alleles may confer advantages in survival or reproduction, leading to natural selection.

In summary, alleles are the alternate forms of genes in nucleic acids that facilitate biological diversity and variability among organisms.