Final answer:
In a long round layer haircut, the hair should be elevated at 90 degrees to create soft, blended layers that contribute to a rounded shape.
Step-by-step explanation:
In a long round layer haircut, the correct elevation at which the hair should be held is 90 degrees. This elevation allows for the creation of a soft layering effect that's blended, without creating bulk or weight lines. Holding the hair at a 90-degree elevation ensures that the layers fall nicely and give a rounded shape as the haircut name suggests.