Answer: 1. principle of uniformitarianism, 2. worms have no hard parts
The principle of uniformitarianism suggests that the geological processes occurring in the past were in the same manner and with the same intensity that as they occur in the present. Therefore, the phrase "The present is the key to the past" rephrases the principle of uniformitarianism.
A worm cannot be fossilized because it does not possess hard parts like bones, shells, teeth as other organisms exhibit. They have tube like body with soft tissues, which gets completely decomposed by microbes after death.