The main difference between the organisms are the uses of the appendage and the size and number of certain bones. The human arm is used for a variety of functions while the lizard's and the cat's are used for walking an climbing, the whale's for swimming, the frog's for support and the bird's and the bat's for flying.
I think that people have lost their jobs because of an increase of computers
A: Taxon.
The terms order and class both refer to 2 specific levels that are a part of Linnaeus' classification systems.