LD50 is used to express TOXICITY OF TOXINS AND POISONS.
LD50 stands for Lethal Dose 50. This is the standard measure of the toxicity of a material, which will kill half of the sample population of a particular test animal in a defined time period, when they are exposed to the material.
Amount of wear, and how long they are may contribute with age and maybe even coloration and pigment.
Answer:
d
Explanation:
look at it it's all over the place