<h3>Answer:</h3><h2>It is because of different arrangements of nucleotide bases.</h2> <h3>Explanation:</h3>
There are only five types of nucleotide basis are present in the genetic material which makes up the all the genetic information of the individuals. These nucleotides are named as Adenine, Thymine, Guanine, Cytosine and Uracil. In all the living beings on the earth, these only five nucleotides are present which decides their behavior and functions on the earth. These five bases have features to get any arrangements according to the situation. Their different arrangement at the heredity material makes the difference in all living beings regarding their behavior.
"An allele is a variant form of a gene. Genes come in different varieties, called alleles. Somatic cells contain two alleles for every gene, with one allele provided by each parent of an organism."- Nature .com
