Chromosome pairs contain different versions of genes which are called

Chromosome pairs contain different versions of genes which are called alleles. They are one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome. Humans are called diploid organisms because they have two alleles at each genetic locus, with one allele inherited from each parent. Hope this answers the question.

True, for example the gulf of mexico is surrounded by the us and spain& mexico.