What interal problems does afghanistan have

Which of the following statements best describes what is occurring in the land surrounding the sahara desert? a desertification is increasing, and the desert is expanding. b. fewer people are trying to farm in this semiarid region. c. the desert is shrinking with the increased use of irrigation. d. increased urbanization has resulted in decreased deforestation. select the best answer from the choices provided mark this and return save and exit next submit

The magnitude of an earthquake is typically calculated according to the scale.           a. mercalli   b. fujita   c. richter   d. saffir-simpson  

In which layer of the atmosphere are the particles so far apart that they can travel hundreds of kilometers without colliding with each other? a.exosphere b.troposphere c.mesosphere d.thermosphere