In the United States, we use a period. In the UK, one does not. I have no idea why this is so.
An explanation:
In British English, a full stop replaces one or more letters that have been omitted from a word. 'Mr' represents the first and last letters of the word 'Mister'. No letters have been omitted after the 'r', so there is no full stop. Similarly there is no full stop after 'Dr' (Doctor) or 'Mrs' (Mistress, popularly altered to Missus). No abbreviation that includes the last letter of the original word should be followed by a full stop. To British eyes, that shows ignorance.
Examples of the correct (to British English speakers) use of a final full stop include 'e.g.' (short for 'exempli gratia') and 'i.e.' (short for 'id est'). However, there is a growing tendency to leave out final full stops in abbreviations generally.
Mr and Mrs is correct or Mrs and Mr is correct
In the US it is normally Mr. and Mrs.
No, it is not. "Whose client is Mr. Jackso[n]" or "Who is the client of Mr. Jackso[n]" would be correct sentences.
the correct answer is led, The class will be LED by Mr Jones OR Mr Jones will LEAD the class
No, that is not correct English. The correct English would be:- "Please add Mr. Mark to tomorrow's session".
The correct way to say the sentence is, "Mr. Jones and he ran the fair."
Mr.James' pen.
Mr.Jones and (he, him) ran the fair is correct.
Mr. and Mrs. David Mielke III
The correct punctuation for "Mr. John Doe III" is as shown. The period after "Mr" indicates an abbreviation, while "III" denotes the third in a line of individuals with the same name.
Yes
'Mr Ram, accompanied by his friends, was assembled at the lawn' would be grammatically correct.