Final answer:
The youngest and best-preserved crater in Canada is found in Ontario, and its uniqueness comes from its age and level of preservation. Additionally, Meteor Crater in Arizona is mentioned as a point of comparison, being approximately 50,000 years old and well-preserved.
Step-by-step explanation:
The youngest and best-preserved crater in Canada is located in Ontario, and what makes it special is that it is the youngest and best-preserved among Canadian craters. Although the question refers to the Canadian crater, it's also important to mention that another well-known recent crater is Meteor Crater in Arizona, which is approximately 50,000 years old and is a significant tourist attraction due to its high level of preservation similar to the one in Ontario, Canada. It is essential in geological studies to consider the youngest exposed crustal rocks because exposing such deep rocks requires significant geological processes that provide insight into the Earth's history and formation.