What was maria winkelmanns theory?

was a star of German astronomy who discovered her own comet. As “assistant” to her husband and later to her son, she contributed to establishing the Berlin Academy of Science as a major centre of astronomy.

Explanation:

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.

the correct answer is a) egypt and china.

egypt and china are two of the world’s oldest civilizations known by man. both ancient empires have left a great historic and cultural legacy to the world through archeology. both civilzations developed complex social relations, had deep religious beliefs, had dominion of agriculture and left writing records to understand their customs and culture.

among the requirements to consider a civilization, we find urbanization, writing records, a place of residence, agriculture methods, technological specialization, means of transportation, currency, population density, social stratification, and political integration.