题干

如图若将某植株一片叶的主脉切断(图中甲),另一片叶两面都贴上不透明的锡箔纸(图中乙),黑暗中放置24小时后再光照4小时.取下两叶经脱色后用碘液处理,发现A部位呈棕褐色,B部位呈蓝黑色,C部位不呈蓝黑色.以上实验能够证明光合作用需要(  )

A:水和二氧化碳

B:叶绿素和阳光

C:水和阳光

D:水和叶绿素

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答案(点此获取答案解析)

C

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    The Van Gogh Museum in Amsterdam has welcomed home two paintings by the Dutch master, more than 14 years after they were ripped (抢) off the museum's wall in a nighttime theft. Museum director Axel Rueger called their return “one of the most special days in the history of the museum.”

    The paintings were discovered last year by Italian police while they were searching suspected Italian criminals' farmhouse near Naples for evidence of drug dealing. The two paintings were wrapped in cotton sheets. They were stuffed in a box and hidden behind a wall in a toilet when they were found.

    The paintings were considered among the artworks most searched for in the world. After years in darkness, they can now shine again. They are back on display at the museum before being taken to the conservation studio for repair. Fortunately, they suffered remarkably little damage as thieves who had climbed up a ladder and broken a window to get into the museum in 2004 rip them out of their frames.

    “It is not only a surprise that the works have been recovered but it's even more surprising they are in relatively unharmed condition,” Rueger said.

    The museum director was on vacation when the call came last year from Italian authorities who believed they had recovered the paintings. He didn't celebrate right away. He'd had calls like this before.

    “I was hopeful but also a little hesitant. Over these years, we had so many occasions when people phoned us, contacted us, claiming that they knew something about the whereabouts (下落) of the works and each time it was false, the trace went cold,” he said. “So...the way has been till of disappointment.” But museum experts sent to Italy to check the authenticity(真实性) of the works quickly turned Rueger's doubts into delight.

    Rueger said the paintings are now back permanently at the museum, which is home to dozens of works by Van Gogh. “I'm very confident that everything is safe in the museum from now on,” he said.