There are no ______ differences between the two products, despite the fact that each is made from different materials.

【正确答案】 D

【答案解析】 空格处的单词应该修饰其后面的名词differences。因此，选项中可以修饰名词的现在分词B和D为正确答案的备选项。D意“可见的”，符合题意。