Answer:
During WWI science was put to use in combating disease leading to a dramatic decline in the amount of soldiers falling to disease.
Step-by-step explanation:
The other explanations don't really fit since your just innovating or adding small features to what already exists. True sciences is used to combat something new or unknown and you invest heavy research into it. Modifying a truck or a weapon isn't so scientific but mostly an engineering feat but creating vaccines for disease is.