Glassy, because luster refers to its ability to shine/sparkle etc
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.
Because the molecules that are being transported is moving against its concentration gradient. in other words, its moving from where its low in concentration to where its high in concentration
