Problem: Text: Mother's Day in the United States is an annual holiday celebrated on the second Sunday in May. Mother's Day recognizes mothers, motherhood and maternal bonds in general, as well as the positive contributions that they make to society. It was established by Anna Jarvis, with the first official Mother's Day celebrated at St. Andrew's Methodist Church in Grafton, West Virginia, on May 10, 1908. In the United States, Mother's Day complements similar celebrations honoring family members, such as Father's Day, Siblings Day and Grandparents Day.

Question: is mother's day always the second sunday of may?
A: yes

Problem: Text: According to the theory of relativity, no information can travel faster than the speed of light in vacuum, but this does not mean that the refractive index cannot be lower than 1. The refractive index measures the phase velocity of light, which does not carry information. The phase velocity is the speed at which the crests of the wave move and can be faster than the speed of light in vacuum, and thereby give a refractive index below 1. This can occur close to resonance frequencies, for absorbing media, in plasmas, and for X-rays. In the X-ray regime the refractive indices are lower than but very close to 1 (exceptions close to some resonance frequencies). As an example, water has a refractive index of 6999999999740000000♠️0.99999974 = 1 6993260000000000000♠️2.610 for X-ray radiation at a photon energy of 6985480652946099999♠️30 keV (0.04 nm wavelength).

Question: is it possible to have a refractive index less than 1?
A: yes

Problem: Text: In baseball in the United States and Canada, the seventh-inning stretch is a tradition that takes place between the halves of the seventh inning of a game -- in the middle of the seventh inning. Fans generally stand up and stretch out their arms and legs and sometimes walk around. It is a popular time to get a late-game snack or an alcoholic beverage as well, as vendors end alcohol sales after the last out of the seventh inning. The stretch also serves as a short break for the players. Most ballparks in professional baseball mark this point of the game by playing the crowd sing-along song ''Take Me Out to the Ball Game''. Since the September 11 attacks, many American ballparks complement or replace the song with the playing of ''God Bless America.'' If a game goes into a fifth extra inning, a similar ''fourteenth-inning stretch'' is celebrated (as well as a possible ''twenty-first inning stretch'' or ''twenty-eighth inning stretch''). In softball games, amateur games scheduled for only seven innings, or in minor-league doubleheaders, a ''fifth-inning stretch'' may be substituted.

Question: do all baseball teams sing the 7th inning stretch?
A:
no