LACs have few (or no) graduate degree programs.
They have few (or no) pre-professional majors (in fields such as architecture, engineering, nursing).
Their mission is to broadly educate thought leaders for academia, civic life, government, and the national economy.
Research universities do that too, but also train specialists. They grant graduate and professional degrees (including Master’s degrees, MDs, and PhDs). Their undergraduate divisions provide opportunities for PhD candidates to practice teaching. Their primary mission is create and share knowledge (including theoretical knowledge to increase understanding of many subjects, as well as applied knowledge to benefit American industry, agriculture, government, finance, national defense, health care, etc.)