题目

The youngest of five children in a middle-class family, Clara Barton was born on Christmas Day, in 1821, in Oxford, Massachusetts. Although she was educated at home, Clara began teaching school herself at the age of fifteen until 1854. Later, before the Civil War (内战), Clara’s greatest achievement was the establishment (建立) of a free public school in Bordentown, New Jersey. What’s more, her only medical experience was when she cared for her invalid (病弱者) brother for two years. When the Civil War broke out, Clara soon learned that many of the wounded soldiers had suff下列有关细菌的叙述中，错误的是（　　）A．细菌分球菌、杆菌和螺旋菌三类B．细菌都寄生在其他生物体内C．绝大多数细菌的营养方式为异养D．对二氧化碳等物质循环起重要的作用