Add-on to the previous post, because I don't want you to get an excessively simplistic idea here.
Specifically...
The construction "[____1____] as well as [____2____]" can also be written with a list of more than one item in location 1.
The context has to be right for this sort of thing, by the way.
E.g., If you have four objects (W, X, Y, Z) that all play the same role in context, that all have the same overall grammatical functionailty, and that are all equal-priority items (= "they'd make sense as a simple list of bullet points"), you should just write a simple list of four parallel items ("W, X, Y, and Z").
If a simple unadorned list is the right construction, then you should not even think of embellishing it into something like "W, X, and Y as well as Z".
On the other hand, if 'Z'—and only 'Z'—is the standard/obvious/default/widely-known/commonsense option for something, and W, X, and Y are unusual/non-default/little-known/non-commonsense possibilities, then
W, X, and/or Y as well as Z
is the best way to write the sentence.
E.g.,
Women often take estrogenic birth-control pills to mitigate the severity of menstrual pain, regulate blood-serum levels of sex hormones, or reduce the appearance of acne as well as to help prevent pregnancy.
In this sentence, "help prevent pregnancy" is, of course, the commonsense default use case that literally every single random person on the street knows for birth-control pills (and even if not, this use can be deduced from the name "birth-control pills"!).
The other three uses are much less well known—a relation that's precisely expressed by putting them all on the left side of "as well as".