'when more than one are' is the correct phrase.
I am, you are, he/she/it is, we are, they are.
That is the correct spelling of the word "multiple" (more than one, or a higher number).The correct spelling is multiple (more than one, many).
That is the correct spelling "princesses" for more than one princess.
that is 'antennae' .
Correct. Two lines never meet in more than one point.
Parenthesis is for one and parentheses is for more than one.
depends if it is more than one
One vertebraTwo or more vertebrae(Vertebrae is the more correct but vertebras is still acceptable)
Either is correct, although in some contexts one may be more common than the other.
No. The correct way is this It is Congress's turn to make a decision. Congress' means "it is owned by more than one congress" or "there is more than one congress" Either one... I'm not sure. Sorry
One is not "more correct" than the other: to you and meis correct, and to you and I is barbarously wrong.
Ally is the singular form. Allies is plural, (more than one).