tv/ movies: who starred as kotter in welcome back kotter?

Questions

In which month does the Quarter Day in Scotland known as Martinmas fall?

Which museum houses the Venus de Milo?

If two ships are on a collision course, what do the rules of the sea require them both to do?

What 1974 book starts "i can see by my watch, without taking my hand from the left grip of the cycle, that it is eigth thirty in the morning?

The symbol of which apostle is a club, the weapon by which he was killed?