سؤال قراءة ستيب محلول — فهم التفاصيل (تدريب 6669)
استيعاب المقروء
Western Europe does not receive enough UV rays in sunlight A lack of the vitamin therefore results in poor calcium and phosphorus deposition in bones, leading to softening. What causes Western Europeans to have little vitamin D?
What causes Western Europeans to have little vitamin D?
