题干

在做叶绿体中色素提取和分离实验时,某同学发现滤纸条上层析出的四条色素带的颜色都较浅,分析其中的原因不正确的是(  )

A:提取色素时忘了加少量的二氧化硅

B:提取色素时加的无水乙醇量偏多

C:所用材料不新鲜,放置时间过久

D:画滤液细线时没有重复画1一2次

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答案(点此获取答案解析)

C

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    Natalie Doan, 14, has always felt lucky to live in Rockaway, New York. Living just a few blocks from the beach, Natalie can see the ocean and hear the wave from her house. "It's the ocean that makes Rockaway so special," she says.
    On October 29, 2012, that ocean turned fierce. That night, Hurricane Sandy attacked the East Coast, and Rockaway was hit especially hard. Fortunately, Natalie's family escaped to Brooklyn shortly before the city's bridge closed.
    When they returned to Rockaway the next day, they found their neighborhood in ruins. Many of Natalie's friends had lost their homes and were living far away. All around her, people were suffering, especially the elderly. Natalie's school was so damaged that she had to temporarily attend a school in Brooklyn.
    In the following few days, the men and women helping Rockaway recover inspired Natalie. Volunteers came with carloads of donated clothing and toys. Neighbors devoted their spare time to helping others rebuild. Teenagers climbed dozens of flights of stairs to deliver water and food to elderly people trapped in powerless high-rise buildings.
    "My mom tells me that I can't control what happens to me," Natalie says. "But I can always choose how I deal with it."
    Natalie's choice was to help. She created a website page matching survivors in need with donors who wanted to help. Natalie posted introduction about a boy named Patrick, who lost his baseball card collecting when his house burned down. Within days, Patrick's collection was replaced. In the coming months, her website page helped lots of kids: Christopher, who received a new basketball; Charlie, who got a new keyboard.Natalie also worked with other organizations to bring much-need supplies to Rockaway. Her efforts made her a famous person. Last April, she was invited to the White House and honored as a Hurricane Sandy Champion of Change.
    Today, the scars of destruction are still seen in Rockaway, but hope is in the air. The streets are clear, and many homes have been rebuilt. "I can't imagine living anywhere but Rockaway," Natalie declares. "My neighborhood will be back, even stronger than before."