Final answer:
The art movement known for organic and fluid curvilinear lines in the late 19th and early 20th centuries is Art Nouveau, characterized by decorative, nature-inspired designs and influential artists like Alphonse Mucha and Gustav Klimt.
Step-by-step explanation:
The Art Movement of the 19th-20th Centuries: Art Nouveau
The art movement that focused on organic and fluid curvilinear lines in the late 19th and early 20th centuries is known as Art Nouveau. Art Nouveau was characterized by its decorative and ornamental style, often featuring asymmetrical designs that drew inspiration from forms in nature, such as insects, flowers, and their twisting growth. This movement was prevalent in various art forms, including painting, prints, architecture, glass, furniture, and jewelry. It began in the 1890s in Europe and America, drawing influence from Japanese art Ukiyo-e, and continued until the onset of World War I.
Artists like Alphonse Mucha and Gustav Klimt were prominent figures in this movement, with Klimt's work being emblematic of its style. The portrayal of women as both subject and object in a decorative context was significant during the Art Nouveau era, reflecting the social attitudes and fashion changes of the time, particularly as women transitioned from Victorian dress to freer clothing that suited the new working roles they began to embrace.