Final answer:
The sentence about men's grooming after the world wars helps develop the central idea related to the impact of world wars on fashion and societal trends.
Step-by-step explanation:
The sentence "After both world wars, men again embraced short hair and the clean-shaven look that signified patriotism and modern life." helps develop the central idea of: A. The impact of world wars on fashion. This sentence illustrates how global conflicts influenced societal trends, including those related to personal grooming. The return to short hair and a clean-shaven appearance among men post-war correlates with a wider societal shift towards embracing patriotism—often shown through uniformity and a departure from the pre-war fashions—and modernity, as the world looked to move forward from the destruction of war. Significant changes in men's grooming preferences reflected broader cultural, social, and economic shifts that were influenced by periods of intense upheaval like the world wars.
In the context of the provided references, this sentence underscores the deep connection between significant historical events and the evolution of societal norms. It indicates that both World War I and II had a pronounced effect on shifting fashion and aesthetic norms, including the move towards more practical and symbolic styles that represented the collective sentiment of the era. Sentiments of nationalism and modern perspectives transcended into everyday life, affecting even the most mundane aspects, such as grooming habits.