The Test on Geologic Time consists of 18 questions. Correct answers are found through links located at the end of each question. The answer section is formatted for on-screen use, not printing, and will waste a lot of paper if printed directly. There are two processes involved in the making of petrified fossils, and they are not restricted to just wood.
Petrified wood is formed by both processes over a long period of time.
As it decayed, the original wood was replaced by mineral matter. A fossil is any evidence of former life, so the term means more than fossilized remains. Evidence can include actual or altered remains of plants and animals such as an insect entombed in amber or a frozen mammoth. It could also be just simple evidence of former life such droppings from bats in a cave. Pot shards from an ancient tribe are therefore not fossils.