Winston churchill coined the phrase "iron curtain" in reference to what?

the construction and maintenance of the berlin wall separating the east from the west

the buffer zone between the soviet union and western europe, composed of communist nations

why were chinese leaders concerned about u. n. forces invading north korea?

they thought this might cause a war with russia.

they believed the enemy would invade them next.

north korea was a longtime ally of red china.

their nation was not prepared to carry on a war.

the extreme differences in ideologies between the soviet union and the rest of eastern europe