The leading causes of global micronutrient deficiencies among the options provided are:
- a lack of dietary variety.
- the lack of nutrient dense foods.
While poor and crowded housing conditions and unavailability of proper sanitation can contribute to overall health issues, they are not direct causes of micronutrient deficiencies in the same way that inadequate dietary variety and lack of access to nutrient-dense foods are. Micronutrient deficiencies typically arise from insufficient intake of essential vitamins and minerals due to a poorly balanced diet.