题干

在培养玉米的溶液中加入某种负离子,结果发现玉米根细胞在吸收该种负离子的同时,对Cl﹣的主动吸收减少时,而对K+的主动吸收并没有影响,原因是(  )

A:该种负离子妨碍了能量的生成

B:该种负离子抑制了主动运输

C:该种负离子抑制了细胞呼吸

D:该种负离子载体和Cl﹣的相同

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答案(点此获取答案解析)

D

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    Sticking to a vegan(纯素食的)diet might sound difficult. ____ According to Huffpost, more than 3 million people in the US are vegans. And in the UK, about 542,000 people turned vegan during the last decade.

    ____

    One reason could be that people want to reduce greenhouse gas emissions(排放). ____ In fact, it's believed to account for 18 percent of the world's greenhouse gas emissions, according to a 2013 study by the UN Food and Agriculture Organization. This amount is even greater than that of all the world's cars, trains and planes combined.

    A growing number of people are also starting to believe that it's wrong to kill animals for food. Therefore, some of them made an ethical(道德的)choice to become vegan.

    ____Vegan celebrities often use social media to spread the message of veganism and share tips on how to live a vegan lifestyle.

    But experts also want to remind people that meat is important for our health. ____ So, if you're thinking about becoming vegan, you should do some research before making your decision.

A. Meat production is very bad for the environment.

B. So why exactly has veganism become so popular?

C. It is up to you to decide whether to go vegan or not.

D. Social media is also believed to be behind the increase in veganism.

E. Fresh fruits and vegetables, grains and nuts are all key to a vegan diet.

F. But in recent years, veganism has become a popular lifestyle in many places.

G. They say that a strict vegan diet may not offer everything that the human body needs.