Ineed . (1) chimpanzees, skillful tool-users, use several objects found in their environment as tools. (2) first of all, they use sticks. (3) they have been seen inserting carefully trimmed sticks into termite mounds and then withdrawing the sticks and eating the termites that cling to them; they also are known to use sticks to steal honey from beehives. (4) in addition, chimps use leaves in a variety of ingenious ways. (5) for example, they have been seen rolling leaves into cones to use as drinking cups, dampening them and using them to clean their bodies, and chewing them until they can serve as sponges. (6) finally, chimpanzees have been observed using stones to crack open nuts. 1. in general, the major details of this paragraph are a. ways chimpanzees learn to use objects as tools. b. reasons chimpanzees use objects as tools. c. examples of objects that chimpanzees use as tools. d. ingenious ways that chimpanzees use leaves.
The second major detail in the paragraph is indeed introduced by c. sentence 4.
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. The first detail talks about sticks, and is introduced by sentence 2. The second major detail talks about leaves, and is introduced by sentence 4. Finally, the third detail is about stones, and is introduced by sentence 6.
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.