Most explosives used in terrorist incidents are characterized as:

The correct answer highlights that most explosives used in terrorist incidents are often made from easily obtainable materials. This characteristic is crucial because it reflects the accessibility of certain substances that can be combined to create powerful explosives. Terrorists typically seek materials that can be acquired without drawing attention, allowing for the effective production of improvised explosive devices (IEDs).

The availability of these materials often includes common household items, fertilizers, and industrial chemicals that can be legally purchased or accessed from various sources. This ease of acquisition is a significant factor that enables individuals with malicious intent to carry out attacks, making it a predominant feature of explosives in such incidents. Understanding this context is vital for law enforcement and safety professionals, as it underscores the need for vigilance in monitoring not just actual explosives but also the precursors and components that can be misused for harmful purposes.