Final answer:
It is true that the slump should be adjusted to the level specified in the mix design; the slump is a measure of concrete's consistency, critical for achieving the desired properties of the final concrete product.
Step-by-step explanation:
The student's question refers to concrete mix design, where the slump refers to a measure of concrete's consistency or fluidity. It is true that you should increase the slump to the level specified in the mix design. A proper mix design includes a slump specification to ensure that the concrete is of the right consistency for the work at hand. If the slump is too low, the concrete may be too stiff to properly work with, and if it's too high, it could compromise the concrete's strength and durability. Thus, it's essential to adjust the slump according to the mix design's specifications to achieve the desired concrete properties.