Final answer:
Clara Bow earned the nickname 'It' Girl for her portrayal in the movie 'It' where she showcased her charm, sex appeal, and vivaciousness. As a flapper, she represented the modern woman of the 1920s.
Step-by-step explanation:
Clara Bow: The 'It' Girl of the 1920s
Clara Bow earned the nickname 'It' Girl due to her portrayal of a salesperson working in a department store in the romantic comedy film, 'It'. Released in 1927, this movie showcased Bow's charm, sex appeal, and vivaciousness, which resonated with the audience.
Bow's accomplishment of becoming the 'It' Girl stemmed from her ability to embody the spirit of the modern, independent and liberated woman of the 1920s, commonly referred to as a 'flapper'. She represented the carefree attitude, fashionable style, and flouting of traditional societal norms that appealed to the generation at that time, making her an icon of the era.