One of the best ways to reduce our impact on the environment is by changing what we eat. Researches show us that we can have the biggest impact by eating less meat and dairy or substituting lower-impact meats such as chicken and pork for beef and lamb. But I’m often asked the question： “What about fish and seafood？ Is that an environmentally-friendly option？”

“Environmental impact” can mean very different things： greenhouse gas emissions， land use， water use or chemical pollution. It’s useful to look at all of these impacts in case there are large trade-offs between them.

In a new study published in Nature， Jessica Gephart and colleagues conducted a meta-analysis of the impacts of fish and seafood across multiple environmental metrics（指標(biāo)）. To do this， they combined life-cycle analysis data from studies of wild-caught and farmed seafood products. It covered over 1690 fish farms and 1000 records from fisheries.

Here， we’re looking at five key metrics： greenhouse gas emissions， land use， freshwater use， and nitrogen（氮） and phosphorus（磷） pollution. Comparing fish to other types of fish is useful. But we also want to know how seafood compares to other protein foods. So， we’ve included chicken for comparison. Chicken tends to have the lowest environmental impact of meat and dairy products – much less than beef and lamb and a bit better than pork. So when we make this comparison， we’re really seeing how seafood compares to animal protein with the lowest impact.

Overall， we see that a lot of seafood has a relatively low environmental impact compared to animal protein sources. Many types have a lower carbon footprint than chicken （those that are higher are around 20-30% higher）. Most farmed seafood needs less land and freshwater and causes less nitrogen and phosphorus pollution. This is because fish tend to be more efficient than chickens in converting feed into meat， which means they need less feed per kilogram.

（材料選自O(shè)ur World in Data網(wǎng)站，有刪改）

1. What is the purpose of the question in the first paragraph？

A. To highlight the benefits of beef.

B. To support the consumption of pork.

C. To emphasize the importance of meat.

D. To introduce the topic about seafood.

2. Which of the following is true about the new study？

A. It was carried out by Jessica Gephart.

B. It was published in various magazines.

C. It involved a large number of fish farms.

D. It highlighted wild-caught seafood products.

3. How does the author analyze the environmental impact according to paragraph 4？

A. By making comparison.

B. By listing data.

C. By explaining the concept.

D. By giving an illustration.

4. Why do fish have a lower carbon footprint than chicken？

A. They need lower levels of protein sources.

B. They require less food to generate meat.

C. They lead to lighter pollution.

D. They cut the use of water.

1.D。解析：推理判斷題。材料第一段的最后一句提到“但我經(jīng)常被問(wèn)到這樣一個(gè)問(wèn)題：魚和海鮮怎么樣？這是一個(gè)環(huán)保的選擇嗎？”下文則主要介紹一些對(duì)比研究，得出海鮮養(yǎng)殖對(duì)環(huán)境影響的結(jié)論，因此該問(wèn)題的寫作意圖是引出話題，故選D。

2.C。解析：細(xì)節(jié)理解題。材料第三段的最后一句提到“它覆蓋了1690多個(gè)養(yǎng)魚場(chǎng)和1000份漁業(yè)記錄”，由此可知該研究涉及了大量的漁場(chǎng)，故選C。

3.A。解析：寫作手法題。第四段的最后一句提到“所以當(dāng)我們進(jìn)行這個(gè)比較時(shí)，我們真正看到的是海鮮與動(dòng)物蛋白相比，對(duì)環(huán)境的影響是最低的”，由此可知使用的是對(duì)比的寫作手法，故選A。

4.B。解析：推理判斷題。材料最后一段的最后兩句提到“大多數(shù)海鮮養(yǎng)殖需要更少的土地和淡水，造成的氮磷污染也更少。這是因?yàn)樵趯暳限D(zhuǎn)化為肉類方面，魚往往比雞更有效，這意味著它們每公斤需要的飼料更少”，B選項(xiàng)與材料內(nèi)容相符，故選B。