While most armies in the world shun their use, and military authorities exclude them from

warfare, the technology to produce biological and chemical weapons is widely available around the world.【C1】______, these weapons are cheap, easy to conceal, and very【C2】______. Since September 11, 2001, biological weapons【C3】______to have become the weapon of choice among the desperate【C4】______of the world. Some people are worried chemical warfare may【C5】______, which would bring an unbelievable disaster to the whole world.

Chemical weapons are【C6】______in variety. Their effectiveness can be【C7】______by several factors, including age,【C8】______, weather conditions, and choice of dissemination. They include nerve agents, blister agents, and choking agents, all of【C9】______can be ingested through the eyes, lungs, or skin. Satin, a type of nerve gas, was used【C10】______the Aum Shinrikyo cult in March 1995, killing 12 people and【C11】______more than 5,500 on a Tokyo subway.

Biological weapons, by【C12】______, are any infectious agent, such as a bacterium or virus, used deliberately to【C13】______harm on soldiers and civilians alike. This【C14】______can include toxin and poison derived biologically. Biological weapons can be produced nearly【C15】______, from government labs to suburban kitchens.

Experts contend, however, that the【C16】______of a deadly virus or bacterium into an effective weapon is anything【C17】______straightforward: A conventional bomb would likely destroy the germ as it【C18】______. In contrast, dissemination【C19】______alternative methods, such as surface mail, has recently【C20】______quite effective.

【C1】

A．Moreover

B．But

C．Therefore

D．Otherwise