Most macaroni and cheese dishes are calorie dense. They're also high in fat and have few nutrients, so keep the portion sizes small. If you make macaroni and cheese at home, you can lighten the calorie load by reducing the butter content and using skim milk or reduced-fat cheeses.
Grading in education is the process of applying standardized measurements of varying levels of achievement in a course. Grades can be assigned as letters (generally A through F), as a range (for example 1 to 6), as a percentage of a total number of questions answered correctly, or as a number out of a possible total (for example out of 20 or 100).
What is hierarchy? Answer Wiki. A hierarchy is A body of persons or things ranked in grades, orders, or classes, one above another; specifically in Natural Science and Logic, a system or series of terms of successive rank (as classes, orders, genera, species, etc.), used in classification.  From the OED .