People from Finland call Valentine's day Ystävänpäivä. What does that mean?

Roman builders used rows of arches in there buildings to form a curved ceiling called what

Whenever there is a vacancy in the office of the vice president, the president shall nominate a vice president who shall take office upon confirmation by a majority vote of both houses of congress

Commercial agriculture consists of raising food for trade and profit, while subsistence agriculture focuses on -- a. providing the basic needs of the farmer's family b. providing the basic needs of the neighboring communities c. creating more arable land for future use d. obtaining subsidies from governments and corporations