Variations in elevation of a land surface is

Variations in elevation of a land surface is relief (or terrain)

Relief also known as terrain is the variations in elevation of a land surface. The relief of an area is the difference in elevation between the highest and lowest dimensions of the area. Relief helps to indicate the direction, height, and angle of slope of many physical geographical features such as plains and mountains in a particular region on the earth surface.

image result for how many calories of energy will 20 grams of carbohydrates provide in one gram provides 4 calories

consuming the right balance of protein, carbohydrates and fat can you maintain a healthy weight and optimize your energy levels. protein and carbohydrates both contain 4 calories per gram, while fat provides 9 calories per gram.