Which of the following improves the fertility of soil by breaking down once-living matter and aerating soil?
a. rock particles
b. sunlight
c. plant roots
d. worms

The earth's internal process which drives seafloor spreading is

What was the most difficult obstacle to overcome in the creation of an autonomous state after indian independence was achieved? a british willingness to go to war to retain the region b. religious differences between hindus and muslims c. ethnic differences between tribal regions d. indian princes' inability to decide on a format of government

Which of the following is a way that advancements in technology improve humans' ability to measure air quality and protect human health?