A square pyramid will not have any curved faces.
None.
5
There are no curved edges on a triangular pyramid.
There are none
none
There are no curved edges, but it does stack.
None. All faces on a pyramid are flat.
There are infinitely many possible answers. A square based pyramid is one.
This is a popular topic, discussed in many places on the web. The attached link is one place that I like. If you want to look for others just google for surface area square pyramid.
None.
5