What defines a "biological weapon"?

A biological weapon is specifically characterized as a microorganism or toxin that is deliberately utilized to inflict harm or death on humans, animals, or plants. This definition encapsulates the intent behind the use of these agents, distinguishing them from naturally occurring pathogens or toxins that do not have a malicious purpose.

The focus on intent is crucial. A biological weapon is utilized as a means of warfare or terrorism to achieve a desired effect, such as causing illness, incapacitating individuals, or instilling fear. This contrasts sharply with options that suggest non-malicious uses.

For example, a microorganism or toxin used for recreational purposes does not fit into the category of biological weapons since the intent is not to cause harm. Similarly, a common virus that spreads naturally through the air lacks the premeditated malicious intent that defines a weapon; it is simply a viral agent that exists in nature. Lastly, although genetically modified organisms can have significant impacts on health, those with therapeutic intent aim to treat diseases or improve health outcomes rather than to harm. Thus, the emphasis on deliberate use in the definition of a biological weapon is what solidifies choice B as the correct answer.