Final answer:
Molecular systematics is a classification system that uses DNA sequences to determine species relatedness. It involves comparing genes or proteins among different organisms and constructing phylogenetic trees based on sequence similarities.
Step-by-step explanation:
Molecular systematics is a classification system for molecular sequences that uses information at the DNA level to determine species relatedness. It involves comparing sequences of genes or proteins among different organisms and constructing phylogenetic trees based on the similarities and differences in these sequences. The more similar the sequences are between two organisms, the more closely related they are assumed to be. Different genes evolve at different rates, so rapidly evolving sequences are useful for determining relationships among closely related species, while slowly evolving sequences are useful for determining relationships between distantly related species.