Why was irrigation important to Sumer? A.)It led to the invention of the sail.
B.)It helped create food surpluses.
C.)It led to trade with other city-states.
D.)It moved water from mountains to city-states.

It helped create food surpluses

Explanation: irrigation is about crops, it's to help grow crops where they wouldn't be able to otherwise. So it would help create food surpluses if they were growing more crops.

explanation:

allergens: overstimulate the nerve system

neurotics: attack nerve cells

mutagens: damage or otherwise alter dna sequence

generators: cause defects during growth and development  

carcinogens: cause unchecked cell growth

i hope you get the idea according to me these are the effects that happened.

i believe the answer is: returns on investments, no wages

people who belong in upper class society would most likely get there by obtaining multiple source of income, which a certain percentage of ownership for businesses. since most of them are job creator, they would most likely get their money from profit, not wages.