An airplane flying at 35 000 feet is above what percent of earth's atmosphere

Seed plants that lived during the carboniferous impact life on earth today because a. they are the ancestors of all plant life on earth. b. their remains formed coal, which is an important resource. c. they produced fossils that are used to date many geologic events. d. their presence caused oxygen levels to drop, allowing animals to evolve.

The physical processes that create most of earth's physical features, including mountains, are known as

How can studying economics us make better choices about how to use scare resources