Are different forms of the same gene that are always found on the same position of two homologous chromosomes

Alleles are different forms of the same gene that are always found on the same position of two homologous chromosomes.  An allele is an alternative form of a gene.  The type of allele acquired by an organism is responsible for the genotypic and phenotypic characteristics in an organism.  

a covalent bond, specfically triple bond

examples of nucleic acids are deoxyribonucleic acid (dna) and ribonucleic acid (rna).