What is russia’s main environmental challenge today?
a. continuing the conservation policies of the soviet union
b. increasing industrial production to spare forests and farmland
c. managing its resources without disregarding the environment
d. stopping the use of nuclear and hydroelectric power sources

Afarmer who is grown corn for the past five years notices in the sixth year that the his harvest is significantly smaller, despite an increase in labor on the farm. the following year, the harvest continue to decline. which of the following explanations most plausibly accounts for the reduction in corn yield? a) soil degradation b) desalinization c) better irrigationd) terracing