甲肝病毒属（）
A.肝炎病毒属
B.微小RNA病毒
C.缺陷病毒
D.黄病毒
E.嗜肝DNA病毒
参考答案：B
Nacre is a substance that is ______
A．mechanically manufactured
B．the result of laboratory testing
C．organically secreted by the mollusk
D．present in the chemical composition of freshwater pounds
代料栽培
