Grasslands, such as the prairies of north america,
a. are suitable for corn and wheat, but not suitable for soybeans.
b. are threatened by soil erosion because native grasses have been damaged or destroyed by plowing and overgrazing.
c. support almost no animal life now that the millions of bison that once roamed there are gone.
d. support a rich layer of dense grasses because they receive at least 250 cm (100 in.) of rain per year.

i am a little confused myself with what goes with the letters and what goes with the numbers but ill do my best to you

the cordillera states and grand canyon are along the southwest u.s. and northern mexican pacific.

the great plains and southwest desert are also the prairie and home to many earthquakes too .

the coastal plains have poor soil and many factories started in the south.

is this what u needed? if not i can see what i can do

b.

developed countries have tended to improve the environment, while developing countries have tended to damage it.