问题
问答题 简答题
15世纪文艺复兴时期的城市广场的基本特点？
答案
参考答案：
（1）在城市建设和对现存的中世纪城市广场改造中体现人文主义的价值（2）追求人为视觉秩序和庄严雄伟的艺术效果（3）科学性、理性化程度得到加强（4）运用透视原理、比例法则和美学原则。
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15世纪文艺复兴时期的城市广场的基本特点？
参考答案：
（1）在城市建设和对现存的中世纪城市广场改造中体现人文主义的价值（2）追求人为视觉秩序和庄严雄伟的艺术效果（3）科学性、理性化程度得到加强（4）运用透视原理、比例法则和美学原则。
| About fifty years ago, plant physiologists set out to grow roots by themselves in solutions in laboratory flasks. The scientists found that the nutrition of isolated roots was quite simple. They required sugar and the usual minerals and vitamins. However, they did not require organic nitrogen compounds. These roots got along fine on mineral inorganic nitrogen. Roots are capable of making their own proteins and other organic compounds. These activities by roots require energy, of course. The process of respiration uses sugar to make the high energy compound ATP, which drives the biochemical reactions. Respiration also requires oxygen. Highly active roots require a good deal of oxygen. The study of isolated roots has provided an understanding of the relationship between shoots and roots in intact plants. The leaves of the shoots provide the roots with sugar and vitamins, and the roots provide the shoots with water and minerals. In addition, roots can provide the shoots with organic nitrogen compounds. This comes in handy for the growth of buds in the early spring when leaves are not yet functioning. Once leaves begin photosynthesizing, they produce protein, but only mature leaves can "export" protein to the rest of the plant in the form of amino acids. |
It can be inferred from the passage that, in the early spring, the buds of plants ______.
A．"export" protein in the form of amino acids
B．do not require water
C．have begun photosynthesizing
D．obtain organic compounds from the root