A hexagon has 6 sides and 6 vertices.
Since the number of sides and vertices is different, it cannot be a 2-dimensional shape. The only 3-dimensional shape with 4 vertices is a tetrahedron and that does not have 6 sides. Consequently, there is no such shape.
a shape with 7 vertices
4 vertices and 6 sides
Polygon
Shape has fewer than 6 sides
A hexagon has 6 sides and 6 vertices.
Since the number of sides and vertices is different, it cannot be a 2-dimensional shape. The only 3-dimensional shape with 4 vertices is a tetrahedron and that does not have 6 sides. Consequently, there is no such shape.
A shape with 7 sides.
a shape with 7 vertices
a tetrahedron is a shape with 4 triangular faces, 6 sides and 4 vertices [corners]
4 vertices and 6 sides
A hexagon.
a hexagon
Four sides ⇒ it is a tetrahedron. More commonly, it is called a triangular pyramid.
Polygon
The shape of a triangular based pyramid has 4 vertices, 6 edges and 4 faces