Since they were the ones controling production of food. They were able to produce enough food themselves. Also, civilization started due to people gathered at one place for farming.
C: circular.
The Hubble sequence is a form of classification of galaxies invented by Hubble in 1926. The sequence divides galaxies into three main categories: lenticular, elliptical and spiral. There is a fourth category that is called irregular, where there are the galaxies that do not fit the characteristics to be included in the three previous categories.
This categorization is the most used even today by both amateurs and astronomers.
Trade had a great impact on Sumerian society. Traders traveled to faraway places and exchanged grain for gold, silver, copper, lumber, and precious stones.