It is a rectangle which is similar to the base.
A cylinder has a circular cross section that is parallel to its base.
A rectangular prism has a rectangular cross section whereas a cylinder has a circular cross section
A cylinder has a circular cross section, a square prism has a square cross section.
Circle
If the cylinder is standing on its flat face, the horizontal cross section is a circle. Otherwise, it is a line or a rectangle.
It is a rectangle which is similar to the base.
The shape of a transverse cross section of a cylinder is a circle.
A cylinder has a circular cross-section whereas a cuboid has a quadrilateral cross-section.
You cannot have a 2d cylinder. The 2d cross section will depend on the plane of the cross section.
A cylinder has a circular cross section that is parallel to its base.
A cylinder has a circular cross section, a rectangular prism has a rectangular cross section.
A rectangular prism has a rectangular cross section whereas a cylinder has a circular cross section
A cylinder has a circular cross section, a square prism has a square cross section.
Circle
rectangle
A circle, ellipse, truncated ellipse or rectangle - depending on the inclination of the cross section relative to the cylinder.