Un-happy
The prefix "un-" could be added to the word happy to create the word "unhappy," which means not happy.
A prefix is a group of letters added at the beginning of a word to change its meaning, such as adding "un-" to "happy" to make "unhappy".
Plotting as it stands does not have a prefix. You could add a prefix to it, however; subplotting, unplotting, replotting and so on. Plotting does, however, contain a suffix '-ing', meaning 'to make, perform or create', so, plotting means to make or create a plot.
You could add the prefix af- to it to make the word affluent.
You could add the prefix non- to it to make the word nonstandard.
"Cost" doesn't have a prefix. You could add the prefix ac- to it to make the word "accost."
in-
Plotting as it stands does not have a prefix. You could add a prefix to it, however; subplotting, unplotting, replotting and so on. Plotting does, however, contain a suffix '-ing', meaning 'to make, perform or create', so, plotting means to make or create a plot.
"Possibility" doesn't have a prefix. You could add the prefix im- to it to make the word impossibility.
You could add the prefix im- to it to make the word impossible.
You could add the prefix ad- to it to make the word advantage.
You could add the prefix sur- to it to make the word surround.
You could add the prefix af- to it to make the word affluent.
You could add the prefix non- to it to make the word nonstandard.
"Social" doesn't have a prefix. You could add the prefix un- to it to make the word unsocial.
The current prefix is ex-. You could add the prefix in- to it to make the word inexcusable.
The current prefix is im-. You could add the prefix un- to it to make the word unimportant.
"Cost" doesn't have a prefix. You could add the prefix ac- to it to make the word "accost."