https://storeys.com/mississauga-votes-against-fourplexes/
There can be both & even all of the above. Single family homes, duplexes, multiplex, low-rise apartment blocks & mid to high-rise towers.
https://en.wikipedia.org/wiki/M_City_Condominiums This is the start of taller buildings in Mississauga than what is allowed in very restrictive Vancouver.
https://en.wikipedia.org/wiki/List_of_tallest_buildings_in_Mississauga