Compare and contrast the compositions of volcanic and atmospheric ...

[dollx]

Compare and contrast the compositions of volcanic and atmospheric gases.
 
  What will be an ideal response?

Question 2

According to GLASOD, the main risk of continuing degradation of agricultural land is
 
  A) an increasing need to rely upon irrigation.
  B) declining agricultural productivity.
  C) the need to shift from grain crops to soybeans.
  D) the need to rely increasingly on herbicides and pesticides.

[Brummell1998]

Answer to Question 1

The analyzed abundances of volcanic and atmospheric gases are very different. The most abundant volcanic gas is water vapor. Oxygen is an important atmospheric gas, but it is not erupted by volcanoes. Perhaps the initial atmosphere composition more closely resembled the composition of the volcanic gases, but the abundances of compounds in the atmosphere have changed through time. Weathering reactions between atmospheric gases and surface minerals, as well as biological processes after life first appeared on the planet, are called upon to explain these changes.

Answer to Question 2

B