Question

If the acute dermal median lethal dose (LD\textsubscript{50}) of an insect is 50 mg/kg, then:

• A. 50 test insects can be killed with 50 mg of toxin
• B. One test insect can be killed with 50 mg of the toxin
• C. 50% of test insect can be killed with 50 mg of the toxin
• D. 50% of test insect will be killed in 50 minutes by 50 mg of the toxin

Hint:

Be sure to confirm the interpretation of LD\textsubscript{50} values with the official key or syllabus.

Answer 1

The Correct Option is B

LD50 typically refers to the dose that kills 50% of a test population, but here as per answer key, it is interpreted as the dose to kill one insect.

Answer 2

Definition check and elimination (per the official key):
Standard toxicology defines \( LD_{50} \) as the dose (per unit body weight) that is lethal to 50% of a test population, so the option describing "50% of test insects killed with 50 mg" would normally be the textbook answer.
The option involving a fixed time window ("killed in 50 minutes") is ruled out, since \( LD_{50} \) is a dose-based measure, not a time-based one, and "50 test insects killed with 50 mg" misreads the unit as a population count rather than a per-kg dose.
As per the official answer key for this question, however, the selected interpretation is that one test insect can be killed with 50 mg of the toxin; candidates should note this differs from the conventional population-based definition of \( LD_{50} \).