Lactase deficiency is more common in asian, native american, mediterranean and some african populations than it is among people with northern or western european ancestry. How would you explain why this is so?.

~potters6/te801/biology/biounits/respiration.htm

Glucose, also called grape sugar, blood sugar or corn sugar, is among the simplest and one of the primary naturally occurring sugars. produced naturally by plants as the primary photosynthesis product, it is heavily used by living beings as a main energy source and is necessary for cellular respiration. chemically, it is a monosaccharide carbohydrate and serves as a building block for complex sugars like starch.