No, rectangles do not have congruent sides. Squares have congruent sides.
No. If you made a parallelogram with congruent sides it wouldn't necessarily have congruent angles. A square has to have congruent angles as well as congruent sides.
Every cube has six congruent sides. If it doesn't have six congruent sides, then it's not a cube.
It has 2 congruent sides
It has four congruent sides.
A parallelogram with congruent sides is a rhombus.
It can have two congruent sides but does not have to.
No, it has 4 congruent sides.
A parallelogram has two pairs of congruent sides, and the opposite sides are congruent.
No. A rectangle has opposite sides congruent. If consecutive sides are also congruent, then your rectangle is a square.
It all depends on what kind of polygon it is. It may have no congruent sides or all congruent sides.
A triangle with two congruent sides is an isoscelestriangle. But an equilateral triangle has two congruent sides. (It actually has three congruent sides.) And isosceles triangle is generally described as a triangle with exactly two congruent sides.