The phrase Tom's assistant uses a single proper noun (Tom) with a possession or belonging (assistant). You have written it correctly.
Tom's assistant, a male secretary, graduated at the top of his class.
The businessman introduced us to Tom's assistant.
A possessive pronoun does not take an apostrophe. This is an exception to the rule that an apostrophe indicates the possessive. To write, 'the dog lost it's bone,' is not correct. The correct way is without the apostrophe: 'The dog lost its bone.' 'It's' (i.e., with an apostrophe) is correct only when used as a contraction of 'it is.'
1925 is correct. There's no need for an apostrophe.
The correct spelling is "learnings" without an apostrophe.
yes
The correct spelling is apostrophe.
The correct spelling is apostrophe.
People's
The correct spelling is don't.
"Alzheimer's" is the correct spelling. It indicates possession or ownership by Dr. Alois Alzheimer, who was the first to identify the condition.
Unless it means "it is", there is no apostrophe in "its". See related question.
Apostrophe has only one name. It's apostrophe. The plural is apostrophes.
The correct placement of the apostrophe before "09" in a contraction of "2009" is at the beginning: '09.