专题03 阅读理解说明文+议论文-学易金卷：2023年高考英语二模试题分项汇编（北京专用）

专题03 阅读理解说明文+议论文 1.（2023·北京昌平·统考二模）Do you know forests are one of our planet’s greatest carbon sinks? This means that they absorb an enormous amount of carbon released into the atmosphere, a greenhouse gas that contributes to climate change and the earth’s rising temperature. The poplar tree, standing tall and regal, is known for its fast-growing nature and its gray, white, or black bark. A biotechnology firm in San Francisco, CA, genetically modified poplar trees. According to a four-month study conducted in their greenhouse, the engineered trees grew 53% larger than their normal counterparts and stored 27% more CO2. In February 2023, the company also planted modified poplar trees in southern Georgia. This marks the first time in the United States that engineered trees have been planted outside of a controlled lab setting! All plants experience photosynthesis (光合作用), where sunlight, water, and CO2 are transformed into glucose and oxygen. However, almost all trees release a poisonous substance in the process. To remove this substance, trees must use up newly-produced energy in another step known as photo-respiration (光呼吸作用), which does not produce any energy and releases CO2 back into the atmosphere. To prevent plants from wasting their energy, the biotechnology firm engineered their poplar trees with genes found in green algae. First tested in tobacco plants, the foreign genes change the poisonous substance produced by trees into sugars, so that more energy can be used for removing carbon and tree growth. Researchers from the company are planting their poplar trees on private land that has been previously disturbed, such as abandoned coal mines in Pennsylvania. The modified trees will be planted between natives like sweet gum and bald cypress to boost biodiversity and maintain soil fertility (肥沃). Plant biologist Norberto Martinez from the University of Illinois suggests the engineered poplar trees may not thrive outdoors or will require more water and fertilizer