The answer is C “volcanic activity was more common in the past than it is today
<span>1 inch of rain per year is less than many
of the world's most arid places get.
That's a real desert, and
probably could not support any grass.</span>
In the Sahara desert, which occupies half of the continent of Africa, the
annual rainfall ranges from 0.8 to 3.9 inches per year. You can see that
1 inch per year is near the bottom of the Sahara's range !