Question

1. Fossils are the _____

Answer 1

Fos·silˈfäsəl/nounthe remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock. 
 so B

Answer 2

B. remains or traces of prehistoric life.
A fossil is the remnants of the bones of previous animals that have been buried in silt and have been hardening over time. Usually only animals that lived either in or around the water have been made into fossils.(Because silt is usually found near water.)