Final answer:
The military hazardous materials/WMD marking system is based on two hazards, one of which is toxicity. This system helps in identifying the potential risks associated with substances and ensures safe handling.
Step-by-step explanation:
One of the two hazards on which the military hazardous materials/WMD marking system is based is toxicity. This system, used to identify potential risks associated with chemical substances, is crucial for safety in handling and responding to hazardous materials. Toxicity refers to the degree to which a chemical substance or a particular mixture of substances can damage an organism. The other hazard is the fire hazard, which pertains to the potential of a substance to combust.