Pretty much as the title says - why are modern front wings comprised of many horizontal planes attached with spaces between, instead of one large curving surface? Would that be too complex to manufacture? Or is there an advantage in having the gaps between the sections? Or is it a regulation thing?
A single large aerofoil would generate more downforce but it is much more susceptible to flow separation i.e. it is easy to stall if, for example, the underside of the wing gets too close to the tarmac. This means that the downforce can vary wildly which makes it difficult for the driver to know what he can ask of the front tyres.
Adding slot gaps allows the wing to generate much more consistent downforce which means the driver knows what to expect and so can drive closer to the limit. The wing is also less likely to stall.
The front wing also has a role in shaping the air flow to the rest of the car One important aspect is directing flow around the outside of the front tyre. A lot of the slots and flaps directly in front of the front tyre are concerned with this issue.
If you are more fortunate than others, build a larger table not a taller fence.
a slotted-and-flapped wing will generate more 'lift'/downforce than will an equivalent plain wing
so is always the better one when there is a limit on wing size
but it will generate a amount of drag disproportionate to the 'lift'
eg Boeing and Airbus etc deploy slots and flaps at low speeds (here they are desperate for lift coeff regardless of drag coeff)
and use a plain wing for the other 96% of the flight
FWIW, a single-element wing is simpler to design and manufacture, which is why in 2009 when the front wing rules were dramatically changed, every team started with much simpler looking wings. As time went on and they had time to determine more of the details of where they wanted the air coming off the front wing to go, and thus further develop the front wing, the designs got increasingly more complex.
The rules don't place any limitations on the number of elements to the front wing (as long as it all fits within a defined "box"). The rear wing however is limited to just two elements (a main plane + a single flap that moves for DRS).
