QUES: UN forces retreated to Suwon in the west, Wonju in the center, and the territory north of Samcheok in the east, where the battlefront stabilized and held. The PVA had outrun its logistics capability and thus were unable to press on beyond Seoul as food, ammunition, and materiel were carried nightly, on foot and bicycle, from the border at the Yalu River to the three battle lines. In late January, upon finding that the PVA had abandoned their battle lines, General Ridgway ordered a reconnaissance-in-force, which became Operation Roundup (5 February 1951). A full-scale X Corps advance proceeded, which fully exploited the UN Command's air superiority, concluding with the UN reaching the Han River and recapturing Wonju.

What caused General Ridgway to initiate Operation Roundup?
What is the answer?
ANS: PVA had abandoned their battle lines
QUES: Although the city lost the status of state capital to Columbia in 1786, Charleston became even more prosperous in the plantation-dominated economy of the post-Revolutionary years. The invention of the cotton gin in 1793 revolutionized the processing of this crop, making short-staple cotton profitable. It was more easily grown in the upland areas, and cotton quickly became South Carolina's major export commodity. The Piedmont region was developed into cotton plantations, to which the sea islands and Lowcountry were already devoted. Slaves were also the primary labor force within the city, working as domestics, artisans, market workers, and laborers.

In what year was the cotton gin rejected?
What is the answer?
ANS: unanswerable
QUES: There are a number of aids available to pilots, though not all airports are equipped with them. A visual approach slope indicator (VASI) helps pilots fly the approach for landing. Some airports are equipped with a VHF omnidirectional range (VOR) to help pilots find the direction to the airport. VORs are often accompanied by a distance measuring equipment (DME) to determine the distance to the VOR. VORs are also located off airports, where they serve to provide airways for aircraft to navigate upon. In poor weather, pilots will use an instrument landing system (ILS) to find the runway and fly the correct approach, even if they cannot see the ground. The number of instrument approaches based on the use of the Global Positioning System (GPS) is rapidly increasing and may eventually be the primary means for instrument landings.

What helps pilots fly the approach for landing?
What is the answer?
ANS:
visual approach slope indicator