81. Which of the following farming practices are considered as sustainable farming?
A. planting a few genetic varieties of a single plant species
B. using large amounts of fertilizers and pesticides to increase crop yields
C. using water to irrigate large areas of land
D. growing crops that are adapted to the region where they are grown
82. Depletion of the ozone layer will lead to reduced crop production and impaired immune systems.

Question

81. 	Which of the following farming practices are considered as sustainable farming? 
A.  	planting a few genetic varieties of a single plant species
B.  	using large amounts of fertilizers and pesticides to increase crop yields
C.  	using water to irrigate large areas of land
D.  	growing crops that are adapted to the region where they are grown
82. 	Depletion of the ozone layer will lead to reduced crop production and impaired immune systems.