The answer is Ultraviolet Light
The easiest way for us to obtain a sustainable amount of Vitamin D is by exposing our self to morning sunlight ( which contain ultraviolet light)
Often time, we don't consume enough vitamin D and our body need to get it from our bones, and in order to do that, it need to be activated through enough exposure from sunlght
Proteins are the nutritional class which builds and maintains cells and tissues. The type are often called "structural" since they are like the scaffolding of cells and tissues.
Answer: pathogens
blood borne pathogens consist of HIV, Hepatitis B and C, and many others
