The 2nd one.
Yes. If the opposing manager changes pitchers in the middle of an at-bat, the batter is allowed to switch sides if necessary. Otherwise, the batter must remain on the same side he started on for that at-bat.
Inning---but not during an at bat. Although ambidextrous pitchers are extremely rare.
Depends where they are playing
Keep your eye on the ball from the time it leaves the pitchers hand to when it makes contact with the bat.
In the minor leagues pitchers do not come to bat. They all use the designated hitter rules. In Major League Baseball pitchers come to bat in the National League, they do not bat in the American League where the designated hitter rule is employed. During inter-league play, the All-Star Game and the World Series, pitchers from both leagues come to bat if the game is being played in a National League park.
In the World Series the pitchers only bat when the game is played in the National League park. When the game is played in the American League park the Designated Hitter is used.
A DH is a designated hitter in baseball. The American League uses DH's to bat in the lineup so that the pitchers do not need to actually bat. In the National League there are no DH's and the pitchers must bat just like the other position players.
The only really stand-out difference between the two is that in the National League, the pitchers bat, and in the American League, the pitchers do not bat, and instead there is a Designated Hitter to take their place in the lineup.
The double switch is generally made to change the batting order. If the pitchers spot is due up the next inning switching two players allows the manager to decide which of the two will bat in the pitchers spot.
in baseball it means you can put anyone there at that position except for pitchers since it is an offensieve position and pitchers dont normally bat