During which phase of product development do companies introduce their product model to actual customers

screening/evaluation
business analysis
market testing
commercialization

The answer would be market testing, hope I helped!!

1. b vitamins2. vitamin k3. vitamin d4. examples are walnuts, seeds, tofu5.  total fat, saturated fat, trans fat, cholesterol, sodium, total carbohydrate, dietary fiber, sugars, protein, vitamin a, vitamin c, calcium, and iron.6. 11257. they have to contain reliable information8. less than 10%  9. i didnt read the course so im not surehope that : p