但丁在《神曲》中强调人所赋有的“自由意志”是“上帝最伟大的主张”，他被称为“中世纪的最后一位诗人，同时又是新时代的最初一位诗人”。对其所处时代的最准确的理解是（     ）

完形填空

    Walt Whitman was a famous American poet (诗人). He was born 1 Mary 31, 1819, in Long Island. There were nine2 in his family, and he was the second. 3 he was four years old, his family moved to Brooklyn because his family was too poor. His childhood was restless (不安宁的) and unhappy. 4 the age of 11, he left school. Then he began to 5 a job to help his family. As a young man, Whitman 6 a school teacher, a printer and a newspaper reporter. He was 7 years old when he published his first book of poetry (诗集) in 1855. He 8 itLeaves of Grass. It 9 only twelve poems. The new form of his poetry 10 many people. Whitman was poor and weak during the last years of his life. He died in 1892.

某生态系统中四种生物的数量关系如图所示，假设这四种生物只构成一条食物链，则下列说法不正确的是（　　）