What is a common characteristic of non-flammable materials?

Answer: B — They do not ignite or burn easily

Non-flammable materials are defined by their ability to resist ignition and burning under normal conditions. This characteristic is essential in various applications, particularly in hazardous materials transport and storage, where safety is a primary concern. Non-flammable substances do not catch fire easily and, in many cases, can withstand exposure to flame or heat without igniting. The other choices illustrate characteristics that are not associated with non-flammable materials. For instance, the option suggesting that non-flammable materials catch fire easily contradicts the very definition of non-flammability. Similarly, the notion that these materials explode on contact does not apply; explosions are typically associated with reactive or unstable compounds rather than non-flammable substances. Lastly, the assumption that non-flammable materials must always be liquid is incorrect, as non-flammability can apply to solids and gases as well. Thus, the defining quality of non-flammable materials is their resistance to ignition and burning.