Final answer:
The claim that ballet was first included in Russian opera during the Romantic era is false. Ballet was already a developed art form prior to this period and was used in opera for its expressive potential.
Step-by-step explanation:
The statement that ballet was first featured in Russian opera in the Romantic era is false. Ballet and opera as art forms have a long history of development and are both built on the evolution of classical music and stylized dance forms. During the Romantic era, Romanticism became the first major stylistic development in nineteenth-century art, and it influenced many areas of creativity, including literature, music, and the visual arts. The era was characterized by a focus on the spectrum and intensity of human emotion, with art reflecting dramatic stories and emotional expression. Ballet had already been established long before this period and was featured in operas in various European countries, including France and Italy. By the time of the Romantic era, ballet had already evolved into its own sophisticated art form and was often included in operas to add to the dramatic storytelling.