How did the war of 1812 affect manifest destiny? roads and canals were built. new inventions were constant. the war slowed industrial expansion for 2 years. industry continued to develop and grow.

The answer is C. The War slowed industrial expansion for 2 years.
During the period of war, most of the manufacturing companies are reqiuired to halt their normal operations and asked to contribute the use of their machinaries to produce war-related items, such as weapons, vehicles parts, parts for food supplies, communication device, etc.