13. It can most reasonably be inferred that the beads mentioned in the first paragraph were most likely used as:

Answer and Explanation

Your Answer is

Correct Answer is D

Explanation

The first paragraph mentions that the beads made of these shells were discovered 100,000 years ago, and the first sentence of the second paragraph also mentions that since then (100,000 years ago), shells have been used not only as decorations, but also as Used as tools and currency. So A and D are both possible, but you can only choose one. Combined with the time of "one hundred thousand years ago", D is more appropriate; and expressed in sentences: since then, shells have not only been used as decorations, It can also be used to make... It shows that the use of decorations was there from the beginning, and the others should have evolved in the development of history. In any case, the use of decorations is the most likely.