The answer to the question given is:
<span>better mass production techniques
</span>Better mass production techniques BEST explains the increased totals for all cars made in the 1920s. Henry Ford, together with <span>General Motors and Chrysler emerging as the “Big Three” auto companies, </span> innovated mass-production techniques that became standard, by the 1920s.
D.) Popular Sovereignty is when the power is giving to the states.
Money, resources, soldiers, allies