Dr. gregory erickson studied the fossilized bones of a dinosaur called albertosaurus to determine the age at which individual dinosaurs died. from this data he constructed a survivorship curve.

Abay where the river empties into the sea

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

Droughts cause very arid places such as a desert