Final answer:
José de San Martín played a pivotal role in the revolutions in Latin America by leading the fight for independence in Argentina, Chile, and Peru. His military successes and leadership were instrumental in liberating these countries from Spanish control.
Step-by-step explanation:
José de San Martín played a significant role in the revolutions in Latin America by leading the independence movements in Argentina, Chile, and Peru. In 1816, he successfully gained freedom for Argentina, and then proceeded to lead an army across the Andes mountains to attack the Spanish stronghold in Chile with the help of Bernard O'Higgins. He later joined the fight for Peruvian independence. San Martín's leadership and military successes were crucial in achieving independence in these countries and ending Spanish control in South America.