Final answer:
The true statement about dental amalgam is that it wears at a rate similar to that of tooth structure. Amalgam requires mechanical retention to hold it in place and is relatively easy to manipulate during placement.
Step-by-step explanation:
The student's question about amalgam is related to its properties as a dental filling material. The correct statement regarding amalgam is that it wears at a rate similar to that of tooth structure. Amalgam is a type of dental restorative material commonly used to fill cavities. It is not true that amalgam bonds to tooth structure on its own; it requires mechanical retention. It is also not accurate to say it is time-consuming to place compared to composite resin because amalgams are known for their ease of manipulation. Lastly, a thin layer of amalgam should not be left to seal the cavosurface margins; all excess material should be removed after placement.