will advanced organisms be the same as complex organisms?why?

Yes.

(Here 'advanced' refers to a newer form that is less like the ancestral species. 'Primitive' means an older form that is close to the ancestral species)

Complexity increases with evolution. Most life forms seen today have arisen by an accumulation of changes in body design that allow the organism possessing them to survive better. The first formed organisms are simpler, while the recently formed organisms are more complex. Complexity in design of simpler forms has increased over evolutionary time, so that they ultimately become modern complex form.