关于俄罗斯自然地理特征的描述正确的是( )
A:俄罗斯的东部是高原,中部是平原,西部是山地
B:俄罗斯地理纬度高,所以大部分河流全年都是冰期
C:俄罗斯大部分地区是温带大陆性气候,冬季寒冷漫长,夏季温和短促
D:俄罗斯海岸线漫长,大部分濒临太平洋,小部分濒临北冰洋
粮桑渔畜生态农业系统是江浙平原水网地区典型的高效农业系统,如图表示这一农业生态系统的基本模式.请据图回答下列问题:
(1)从生态系统的组成成分上分析,该生态系统的生产者是____ (举出两个例子),沼气池中的生物属于____ (生态系统的成分).
(2)该农业生态系统基本模式的建立,运用了____ (写出两种即可)等生态工程的基本原理.
(3)图示生态系统与传统生态系统相比,其具有的优点是____.
(4)该生态工程建设中,鱼塘中每一种鱼苗的投放量都不宜超过____ .
(5)请根据下列物质交换关系补充方框中的生态系统的成分____ .
已知三次函数f(x)=ax3+bx2+cx+d的图象如图所示,则f'-3f'1=____
无公害蔬菜的生产属于( )
I'm Peter. There are four people in my family. They are my father, my mother, my grandfather and me. I'm twelve. My birthday is on 15th March. My parents are both doctors. They help people. Their birthdays are both in May. My grandfather is old. He is sixty-five. His birthday is on 9th June. He likes reading. I like reading too. I want to be a teacher in the future. I want to teach Chinese in a school.