What does LD50 stand for?

LD50 refers to "lethal dose for 50% of the test subjects." This term is widely used in toxicology to quantify the toxicity of a substance. It specifically represents the amount of a chemical that, when administered, is expected to cause death in 50% of a defined experimental population, usually laboratory animals.

Understanding the concept of LD50 is important as it provides a measurable standard for assessing the potential harmfulness of chemicals, pesticides, and pharmaceuticals. Assessing LD50 allows researchers to compare the toxicity of various substances and to make informed decisions regarding their safe use.

The other options do not accurately capture the definition of LD50, as they either suggest a complete lethal dose or focus on the onset of symptoms rather than the specific mortality rate that LD50 represents.