Final answer:
Plaster of Paris is indeed used to create casts of impressions, true to the student's statement. It sets quickly and forms hard casts in both medical applications for broken bones and in paleontology to protect and transport fossils.
Step-by-step explanation:
The statement that Plaster of Paris is often used to create casts of impressions is true. Plaster of Paris, which is a quick-setting gypsum plaster consisting of a fine white powder (calcium sulfate hemihydrate), hardens when moistened and allowed to dry.
It is commonly used in medicine to make smooth, hard casts for broken limbs.
In other fields such as paleontology, as described in the reference, a plaster jacket made from sheets of burlap soaked in Plaster of Paris is used to safeguard fossils. The plaster protects the footprints of Cretaceous dinosaurs, which were preserved in an iron-rich clay layer beneath a yellowish sandstone layer, during transportation or study.