题干

我国药学家屠呦呦因研究青蒿素获得2015年诺贝尔医学奖.青嵩素的化学式为Cl5H22O5,下列说法正确的是(  )

A:青蒿素分子由三种元素组成

B:青蒿素是一种有机物

C:青蒿素含有42个原子

D:青蒿素中氢元素的质量分数最大

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答案(点此获取答案解析)

B

同类题3

    Since the 1970s, scientists have been searching for ways to connect the brain with computers. Braincomputer interface(BCI) technology could help people with disabilities send commands to machines.
    Recently, two scientists, Jose Millan and Michele Tavella from the Federal Polytehnic School in Lausanne, Switzerland, show a small robotic wheelchair directed by a person's thoughts.
    In the laboratory, Tavella operated the wheelchair just by thinking about moving his left or right hand. He could even talk as he watched the vehicle and guided it with his thoughts.
    “Our brain has billions of body cells(细胞). These send signals through the spinal cord(脊髓) to the body part to give us the ability to move. But spinal cord injuries(脊柱受伤) or other conditions can prevent these weak electrical signals from reaching the body part.” Tavella says. “Our system allows disabled people to communicate with outer world and also to control machines.”
    The scientists designed a special cap for the user. This head cover picks up the signals from the scalp(头皮) and sends them to a computer. The computer finds meanings of the signals and commands the wheelchair with an engine. The wheelchair also has two cameras that tell objects in its path. They help the computer react to commands from the brain.
    Prof. Millan , the team leader, says scientists keep improving the computer software that finds meanings of brain signals and turns them into simple commands.” The practical possibilities that BCI technology offers to disabled people can be grouped in two kinds: communication, and controlling objects. One example is this wheelchair.”
    He says his team has set two goals. One is testing with real patients, so as to prove that this is a technology they can get advantages from. And the other is sure that they can use the technology for long.