In desertification ________. (Multiple Choice)

In desertification ________.
 
  a. lands are deserted because chemical contamination makes them unsafe for human habitation
 b. marginal agricultural lands are deserted to permit the re-establishment of native communities
 c. large regions of land capable of supporting agriculture are degraded to a desert-like condition
 d. marginal desert-like tracts of land are rehabilitated and put back into agricultural production

Question 2

The contribution an individual makes to the gene pool of the next generation relative to the
  contributions of other individuals is called
 
  a. competition.
  b. genetic drift.
  c. relative fitness.
  d. gene flow.
  e. mutation.