试翻译下面一段话。切忌抄袭,切忌直接利用翻译软件。 Description of Energy Pyramids Describe the paper clips as being "energy units" in a food chain. Give students in the first row three paper clips each and the rest of the students in the class one paper clip. Beginning with the second row (primary consumers), each person in that "trophic level" must find and take three "energy units" from the next "lower trophic level" (i.e., people in the row in front of them). Each person in that higher trophic level then must pay the instructor two energy units to stay alive. If an individual has two or fewer energy units, they are "deceased" and do not participate in the next step. Continue to the next higher trophic level (next row back) until there is a row where only one person has clips left to pay to stay alive (usually about four to six rows from the front). Have the students who stayed alive in each row raise their hands to show the pyramid.