Answer:
The second major detail in the paragraph is indeed introduced by c. sentence 4.
Explanation:
<u>This paragraph offers three major details about the claim. The claim is that chimpanzees are skillful tool-users. Then, the details mention how they can use three different objects in a creative, intelligent manner.</u> The first detail talks about sticks, and is introduced by sentence 2. <u>The second major detail talks about leaves, and is introduced by sentence 4.</u> Finally, the third detail is about stones, and is introduced by sentence 6.
<u>Therefore, to answer the question: the second major detail is introduced by sentence 4 -- 4) In addition, chimps use leaves in a variety of ingenious ways. </u>