条件缺损病毒（coditionally defective viruses）

A . HAV B . HBV C . HCV D . HDV E . HEV

A . 正确 B . 错误

A . 包膜表面刺突缺损 B . 衣壳缺损 C . 基因组缺损 D . 病毒酶有缺损 E . 复制周期不完整

A . A.HAV B . B.HBV C . C.HDV D . D.EBVE E . E.CHO病毒

A . deep water B . shallow water C . stiff soils D . soft soil

A . 委托 B . 佣金 C . 瑕疵 D . 公告

A . HAV B . HBV C . HCV D . HDV E . HEV

A . 包膜表面刺突缺损 B . 复制周期不完整 C . 壳粒变异 D . 基因组缺损 E . 衣壳缺损

A . A、底片因刮伤、擦伤、手纹、污染等造成的显示 B . B、照相技术不良、扭曲、几何形状变化等产生的显示 C . C、物件中属于正常结构以外的不连续状况 D . D、会损害到物件的使用，或超出规范、标准

A . parallel to the longitudinal direction of the chain B . perpendicular to the direction of the anchor chain C . diagonally across the link of the anchor chain D . around the circumference of the chain link

A . smoky exhaust B . starting failure C . ignition relay D . over speed

A . should be paved B . should be cleaned C . should be dismantled D . should be welded

Scientists have discovered a genetic defect that appears to cause deficit-hyperactivity disorder, more commonly known as hyperactivity. People afflicted with this disorder have trouble focusing their attention and controlling impulses, and tend to be rest-less and aggressive. The defect occurs in a gene that regulates the body's use of the thyroid hormone. This finding was made in continuing study organized by the National Institute of Diabetes and Digestive and Kidney Diseases in which 70 percent of children inheriting the gene were hyperactive while only 20 percent of the children not inheriting the gene were hyperactive. And although the researchers admit that this defective gene probably accounts for only a fraction of cases of hyperactivity, this discovery will allow doctors to spot newborn babies likely to have the disorder, and also to provide clues for its cause and treatment.

疯牛病的病原体是 () A、类病毒 B、卫星病毒 C、前病毒 D、缺损病毒 E、朊粒

A．点状坏死 B．桥接坏死 C．碎片状坏死 D．大块及亚大块坏死 E．嗜酸性变及嗜酸小体

A．缺失DNA B．缺损质粒 C．缺失病毒 D．缺失突变体