weren't the best place to study chimpanzee behavior. He dispatched a researcher named Henry Nissen to Africa. The problem was no one had invented a way to observe chimps in their natural habitat. So Nissen relied instead on techniques used by hunters to stalk game. He hid in camoullaged blinds, but the chimps spotted him and scampered off. He stationed assistants in a large circle in the dense undergrowth. Nissen's difficulties discouraged further study of wild chimps until the 1960s. The author explains that the study of chimpanzees stopped in the 1920s and did not start up until the 1960 s.Which two sentences from the text show what caused this gap? A He hid in camouflaged blinds, but the chimps spotted. him and scampered off B The problem was no one had invented a way to observe chimps in their natural habitat. C He dispatched a researcher named Henry Nissen to Africa. D He was slow and backward and spouted strange noises. E observation. Unfortunately, these early humans were not alive for

## Step 1<br />The problem is asking us to identify two sentences from the text that explain why the study of chimpanzees stopped in the 1920s and did not resume until the 1960s. <br /><br />## Step 2<br />We need to analyze each sentence in the text to determine if it provides a reason for the gap in the study of chimpanzees.<br /><br />## Step 3<br />Sentence A: "He hid in camouflaged blinds, but the chimps spotted him and scampered off." This sentence does not provide a reason for the gap in the study of chimpanzees. It merely describes a failed attempt at observation.<br /><br />## Step 4<br />Sentence B: "The problem was no one had invented a way to observe chimps in their natural habitat." This sentence provides a reason for the gap in the study of chimpanzees. It explains that the lack of a method to observe chimpanzees in their natural habitat was a problem.<br /><br />## Step 5<br />Sentence C: "He dispatched a researcher named Henry Nissen to Africa." This sentence does not provide a reason for the gap in the study of chimpanzees. It merely describes an action taken by the researcher.<br /><br />## Step 6<br />Sentence D: "He was slow and backward and spouted strange noises." This sentence does not provide a reason for the gap in the study of chimpanzees. It merely describes the researcher's behavior.<br /><br />## Step 7<br />Sentence E: "Unfortunately, these early humans were not alive for observation." This sentence does not provide a reason for the gap in the study of chimpanzees. It merely describes a situation that is not related to the study of chimpanzees.