Trench warfare in World War I was characterized by... A. Heavy casualties and little territorial gain
B. A series of Russian victories
C. Swift invasions and decisive attacks
D. Tremendous German victories in the East

Mainly Trench Warfare was popularized by the use of new mechanized weapons such as Artillery, and also because of the mass victories in the east on germany's side, Russia used these as a form of slowing them down and to protect their troops, but often these trenches hurt these men by disease, starvation, etc.

d.he wanted to send diplomats to communist countries.

union blockade

explanation:

the union blockade in the american civil war was a naval strategy by the united states to prevent the confederacy from trading.

the blockade was proclaimed by president abraham lincoln in april 1861, and required the monitoring of 3,500 miles (5,600 km) of atlantic and gulf coastline, including 12 major ports, notably new orleans and mobile. those blockade runners fast enough to evade the union navy could only carry a small fraction of the supplies needed. they were operated largely by british citizens, making use of neutral ports such as havana, nassau and bermuda. the union commissioned around 500 ships, which destroyed or captured about 1,500 blockade runners over the course of the war.