Which problems led to the decline of sumer? select all correct answers.
a. fights over boundaries and water rights.
b. constant flooding of the area
c. long dry spells without any rain
d. the cities grew too fast

Which statement best describes standard oil in the late 1800s? standard oil controlled only a small number of the nation’s oil refineries. standard oil was a single business that operated in a small region. standard oil controlled only the means and methods of oil production. standard oil owned ninety percent of all oil refineries in the united states.