Acute toxicity is best described as the ability to harm or kill an organism after:

• A. one exposure
• B. multiple exposures over time
• C. exposure to extreme heat
• D. exposure only in air-tight conditions

Answer: (A)

Acute toxicity refers to harmful effects that appear quickly after exposure to a substance, typically from a single dose or a brief exposure. That means the key idea is rapid, short-term impact, which is captured by the description of harm or death following one exposure. If harm only occurs after many exposures over time, that would be chronic or cumulative toxicity, not acute. Other factors like extreme heat or being in airtight conditions don’t define acute toxicity, since the concept centers on how soon the effects show up after exposure.