题干

水稻的花药通过无菌操作,接入试管,经过如下过程培育试管苗.据图分析下列叙述正确的是(  )

A:a、b、c、d中的植物细胞都具有全能性,且全能性的表达程度相同

B:愈伤植物组织代谢类型为自养需氧型,培养基不需要添加有机物

C:水稻花药经a~d发育成试管苗的过程不涉及减数分裂

D:图中试管苗的自交后代不会发生性状分离

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C

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    Madison Williams was studying in her bedroom in Dublin, Ohio, in August 2016 when the door burst open. It was her mother, Leigh Williams, with a(an)1 story: “A little boy fell into a septic tank (化粪池), and no one can 2him.” Then she made this3 of her 13-year-old daughter: Can you help?

    Madison and Leigh ran to a neighbor's yard, where they found the boy's 4mother and other adults surrounding a septic tank opening. Its diameter was5 wider than a basketball. The boy had 6 in and was drowning in the sewage (污水).

    Madison quickly7 the situation. She was the only one who could 8through the small hole. Without 9 she told the adults, “Lower me in.” Inside, the tank was dark, and the air10 In the process of finding the boy, her left wrist was injured by a hidden pole so11 that the hand was useless. But Madison went on skimming the surface of the sewage, hoping to 12 the boy. “Every once in a while, I'd see his little toes she says. “Then I would try to grab them.” After several failed13 she finally managed to grasp his foot tightly with her14 hand. “Pull me up!” she shouted to the others above. Ten minutes after Madison had entered the tank, she and the boy were15 out.

    But the boy wasn't out of16He had been taken away from oxygen long enough that he wasn't breathing. He was 17 on his side, and an adult gave him several hard beats on the 18 one right after the other, until the boy coughed up liquids. It was only when Madison heard him cry that she knew he was all right.

    It took Madison longer to 19 than the boy. She experienced months of physical treatment for her wrist, which, says neighbor Mary, made the girl's actions more 20.