The development of new varieties of grain crops increased ...

[bobthebuilder]

The development of new varieties of grain crops increased productivity by increasing the
 
  A) surface area of the leaves of the plants.
  B) size of the roots and ability to absorb water.
  C) strength of the stems to support more grains.
  D) size and number of seeds.

Question 2

The future worldwide use of irrigation
 
  A) is expected to double in the next 20 years due to increasing demands for food.
  B) is limited by the availability of freshwater, waterlogging, and salinization of soils.
  C) depends on new technologies to extract more groundwater.
  D) will require increased reliance on new hydrogen technologies to produce freshwater.

[kxciann]

Answer to Question 1

D

Answer to Question 2

B