Out, not, or former
Yes ex- is the prefix of explosion. The prefix ex- means out of or lacking.
The prefix of explored is ex-. This prefix means out of.
The prefix that means "former" is "ex-."
The prefix of exemplify is "ex-" which means out or beyond.
The prefix for expand is ex-. This prefix means out of.
The prefix Extra means beyond. It may often be confused with the prefix Ex or E meaning out.
The two letter prefix which means outside is ex, as in the word, exhale, to breathe out.
Ex- is the prefix for exile. Ex- means away from or lacking.
The prefix for "Horn" is "ex-", which means out of or from.
The prefix of "exceedingly" is "ex-" which means out of or beyond.
ex-
Excavate is not a prefix; it is a word. It does contain the prefix "ex-" which means "out" in this instance.