from the resolv.conf manpage:
Sets a threshold for the number of dots which must
appear in a name given to res_query(3) (see
resolver(3)) before an initial absolute query will be
made. The default for n is 1, meaning that if there
are any dots in a name, the name will be tried first as
an absolute name before any search list elements are
appended to it. The value for this option is silently
capped to 15.
Thus if resolv.conf has
options ndots:0 it will attempt a root domain search immediately and not try any search list domains. The manpage seems to indicate it should try searching if the query domain doesn't exist in the root, but my resolver didn't do that when testing. Otherwise if there is no dot, it tries search elements in order first, then the root domain after exhausting the list. Note, you can set
search . which puts the root domain in the search list.
Another thing to note is your name resolution may never make it to resolv.conf if the request is satisfied by another nsswitch.conf mechanism before it gets there.