What is the name of the large desert that runs across north america

Does anyone know the answers for these

Which of the following is not a place where hydrogen can be found on earth? a. natural gas well b. atmosphere c. water d. mine

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