Here are the vocabulary terms matched with their correct definitions:
1. **Substitution**: a type of mutation in which one nucleotide is replaced by a different nucleotide.
2. **Codon**: a trinucleotide sequence of DNA or RNA that corresponds to a specific amino acid.
3. **Nondisjunction**: refers to a pair of homologous chromosomes failing to separate or segregate at anaphase so that both chromosomes of the pair pass to the same daughter cell.
4. **Insertion**: a type of mutation that involves the addition of one or more nucleotides into a segment of DNA.
5. **Allele**: Different versions of the same gene that arise through mutations and are found at the same place on a chromosome. They can result in variations in the inherited traits of an organism, such as eye color or blood type. Each individual typically inherits two for each gene, one from each parent.
6. **Mutation**: the changing of the structure of a gene, resulting in a variant form that may be transmitted to subsequent generations.
7. **Deletion**: a type of mutation that involves the loss of one or more nucleotides from a segment of DNA.