What is one characteristic of toxic substances?

• A. They have no effect on the environment
• B. They may cause illness or injury when inhaled or contacted
• C. They are always visible
• D. They decompose harmlessly

Answer: (B)

Toxic substances are defined by their ability to cause adverse health effects when they come into contact with living organisms. This characteristic includes a range of potential outcomes, such as illness, injury, or even death, depending on the level of exposure and the specific properties of the substance involved. The capacity of these substances to inflict harm through inhalation or skin contact highlights the critical need for caution and appropriate safety measures when handling or being exposed to them.

In contrast, the other options present characteristics that do not accurately reflect the nature of toxic substances. For instance, the notion that toxic substances have no effect on the environment contradicts their known potential to cause significant ecological damage, including harm to wildlife and habitat degradation. The visibility of toxic substances isn’t a reliable indicator, as many harmful chemicals are colorless or odorless, making them difficult to detect without proper equipment. Lastly, while some substances may decompose harmlessly, this is not a universal trait of toxic substances, as many can persist in the environment and continue to pose risks long after their initial release.