- (C) Median lethal dose (LD 50 ) figures are frequently used as a general
indicator of a substance’s acute toxicity (i.e., the lower the LD 50 , the greater
the toxicity). (A) is incorrect because no amount can ever claim to be 100%
safe. (B) is wrong because a 5 mg/kg, not a 2.5 mg/kg, dose will kill 50% of
the members of the tested population. (D) is incorrect because the dosage
needs to be worded as 10 mg per kg. Furthermore, the dosages are not
usually directly proportional; hence, lethality due to the amount of the dose
administered is often seen as a curve, not as a straight line. Finally, (E) is
incorrect because there is no information provided in the question that refers
to “any dose.” Also, (E) is contrary to the fact that LD 50 = 5 mg/kg.
