what are the factors that determine an individual's nutritional needs?
['Genetics and gender.', 'Dietary energy concentration.', 'Environmental temperature.', 'Health status.', 'Stocking density.', 'Feeding strategy and degree of competition for feed.', 'Variability of nutrient content and availability in ingredients.', 'Presence of molds, toxins, or anti-nutritional factors in the diet.']