Darwin observed fossils of huge animals such as glyptodon why were these fossils of interest to him

I believe its is because the fossils of these animals looked like living species and they had a connection to the modern. A fossil is any preserved evidence of life from a past geological age, such as the impressions and remains of organisms embedded in stratified rocks. Fossils are created when organisms die, are in cased in dirt and rock, and are slowly replaced by minerals over time.

Regular or uniform type

It depends on the surface of the levels. the rougher the surface, the greater is the frictional force. for rougher surfaces, you would need to exert greater force to move the object. the concept is that, you must overcome the frictional force in order to bring the object into motion. this is the reason why we add lubricants to the joints so they could easily move. this answer was on