ASAP I AM DOING A TEST PLEASE I WILL MARK BRAINLIST

Which of the following terms describes the layers of air surrounding the earth ?

Witch of the following volcano hazards is made up of rocky particles about the size of a grain of sand

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