题干

关于生态系统的说法不正确的是(  )

A:生态系统中的生产者固定的太阳能是流经该系统的总能量

B:在生态系统中,物质循环是生态系统能量流动的载体

C:植物光合作用固定的碳与植物呼吸作用释放的碳基本相等

D:能量在相邻两个营养级之间的传递效率的大小是由这两个营养级的同化量决定的

上一题 下一题 0.0难度 选择题 更新时间:2019-04-05 01:51:12

答案(点此获取答案解析)

C

同类题4

阅读理解

    In 1971 a young man who grew up very poor was travelling across the country, trying to make a new start for himself. Along the way he had completely run out of(用光) money and was forced to spend the night in his car. This continued until one morning, after a week of sleeping in his car, he walked nervously into a restaurant and ordered a big breakfast.

    After eating his first good meal in weeks, he found himself lying to the waiter, telling him he had lost his wallet. The waiter, who was also the owner, walked behind the chair where the young man had been sitting. He bent down, and came up with a $20 bill that looked as if it had fallen on the floor and said, “Son, you must have dropped this,” the owner said. The young man couldn't believe his luck! He quickly paid for the breakfast, left a tip, bought gas with the change, and headed West.

    On the way out of town, he began to understand what the owner did. Maybe nobody dropped the money at all. “Maybe that fellow just knew I was in trouble and he helped me in a way that didn't embarrass(使尴尬) me. So I just made a promise to help other people if I can.”

    Later, he worked very hard and became a rich man. Now he lives near Kansas City. Each year he gives away thousands of dollars. He is known as the “Secret Santa” because at Christmas time each year, he personally hands money out to those on the street and at restaurants. Last year, he gave more than $50,000 away in Kansas City.