What’s the summary of this

they required less loading and unloading

explanation:

the shipping container improved shipping because it cut down on unloading time by three weeks, eliminated wasted space, and allowed ships to carry.

the correct answer is a

once he became head of state in 1915, venustiano (his name was not victoriano) carranza was able to implement some of his ideas, such as the drafting and the promulgation of the mexican constitution of 1917, which is still the current constitution of that country.  

were unable to make a profit due to their debt.