Answer:
The early focus of nutrition research was on the 4. Amount and type of nutrients needed to prevent deficiencies.!
Explanation:
Nutrition research is relatively young. One of the first developments was the first vitamin isolated in 1926. During this period of time, research was focused on nutrient deficiency diseases. Researching in the field of non-communicable chronic diseases, like diabetes, obesity, Etc. is recent. All these changes obey to the health context and the common diseases of the different periods of time. Option 1, 2 and 3 are examples of these young area of research.