Final answer:
Operatic vocal lines are usually bel canto style with highly ornamented melodies, showcasing the singer's skills.
Step-by-step explanation:
Operatic vocal lines are characterized by their rich and elaborate style referred to as bel canto, which literally means 'beautiful singing' in Italian. This singing style prioritizes the beauty of the voice and the virtuosity of the singer, often featuring highly ornamented melodies with trills, runs, and other embellishments. These vocal parts are carefully composed to showcase the singer's range, agility, and expressiveness, often requiring significant skill and training to perform. While bel canto and ornamentation are key features of many operas, not all operatic vocal lines follow this tradition; some may be less adorned or use a different vocal aesthetic altogether. However, the most iconic and historical pieces of opera are known for their bel canto and heavily ornamented vocal lines, making this the defining characteristic for such works.