According to this excerpt, how many social classes are now left in American society? What/who are they?

not to sure thinking it would be a hope this

the causes of the dust bowls were severe droughts,   lands became dry and hard, temperature was higher than usual, hot and dry conditions killed crops, high winds. because of those factors, the winds kicked up dry soil and created clouds of dust.

ecologists can be teachers or research scientists. they can work for environmental organizations like the nature conservancy or for the government. they may work at museums, zoos and aquariums.