Final answer:
The overwhelming majority of American troops who died during the Mexican War were killed by disease.
Step-by-step explanation:
The overwhelming majority of American troops who died during the Mexican War were killed by disease. While combat was a significant cause of death, with many soldiers dying from infected wounds, disease was responsible for a larger number of casualties. The unsanitary conditions, lack of medical knowledge, and presence of diseases such as dysentery and yellow fever led to a high mortality rate among the soldiers.
Learn more about causes of death in the Mexican War