When individuality is being emphasized (that is, ‘not one’), a singular form of the verb is used:
“She is difficult to describe physically - none of her features is particularly striking.”
(That is, of all her facial features, not one is striking.)
“It was a quiet night in the restaurant. There was an elderly couple in one of the booths, but none of the other tables was occupied.”
(That is, not one table, not a single other table was occupied.)
When you are considering things as a collective group (the notion of a sub-group within a larger group), use the plural:
“She had many boyfriends and love affairs in her younger years, but none were very serious.”
“Many factors contribute to rampant disease in African countries, but fortunately, none of these are present in South Africa.”
Engee: You once tried to give some explanations concerning the same topic. It was then when you decided not to go on about the topic any further. So why should you do it now? So why should you do it now? So why should you do it now? What kind of school-yard petulance gives with you!
Here, I am responding to a thread by palinkasocsi rather then, as before, deciding to terminate responding to you!
From here on, bleat away. I will be ignoring your posts.