2. why is estimating the number of species on earth so difficult and why do these estimates vary so greatly?

its beacuse there are millions of species in the world, and there are still mre speacies we still dont know about. its impossible to study all of them it will take a great amount of time to discover and study them.but, the most mysterious place is the ocean we know more about space than we know about the ocean. the ocean is sooo HE and  massive it covers 70% of the world, imagine how many species will be in a place that covers 70% we still dont know about.

~batmans wife dun dun dun

the force represented by vector a is normal force. if the hockey puck is moving to the right, when it is hit with a significant force by the hockey stick the puck will move off in a different direction. correct on edge.