What are the two ways that igneous rock are classified? a. by luster and color b. by heft and specific gravity c. by composition and texture d. by radioactivity and polarity

List charasteristics of athenosphere

Which of these is an example of land degradation? a. containers designed to store pollutants leak. b. fertilizers provide too many nutrients to crops. c. garbage is buried so the land can be reclaimed later. d. a drought kills all the plants in an area, leaving bare land

Which of the following is a reason why early living organisms on earth could not have survived on the surface? 1. the lack of an ozone layer 2. the lack of oxygen in the atmosphere 3. the fact that these organisms were single-celled