Why did the instructor describe nutrition as a "relatively new" and "inherently complex" science?

Because it only studies modern processed foods and ignores traditional diets and historical patterns of disease.

Because all nutrients have been fully identified for centuries and the remaining questions are mainly about culinary taste preferences, which makes research trivial.

Because nutrition research primarily focuses on a fixed set of biochemical pathways and has long-standing universal recommendations that never change, therefore complexity is overstated.

Because food composition, human biology, and human behavior interact in many ways and our scientific understanding is still evolving.