parallelogram, because if the two bases are congruent and parallel then the sides will also have to be parallel, so it is a parallelogram
a cylinder!
Triangle
A prism has two congruent parallel bases.
Both a cylinder and a prism can have parallel and congruent bases.
When a base is congruent it is the same shape and size, and parallel is when they will never touch. Therefore, on a square the top and bottom are congruent parallel bases. Some other examples are: Cylinders, rectangular prisms, and of course parallelograms.
Most things do not have two congruent parallel bases. I do not, by desk does not, my lap top does not, etc etc.
An upright pentagonal prism has two congruent parallel bases and 15 edges.
A prism has two parallel and congruent bases in the shape of polygons. Example - a cereal box (is rectangular prism). The top and bottom are rectangles(a polygon). They are the same size and shape (congruent) and also parallel. A cube (think of six sided dice) is a special rectangular prism. Imagine a a box where the top and bottom are triangles (of the shape size and shape). This is called a triangular prism.
prism
no
A square.
Its "bases"