A hemisphere
Yes. I think of an edge as a line. The edges meet at vertices, and the faces meet at edges.
were two or more faces of a solid figure
triangular prism
Any solid object with six faces is a hexahedron. A regular hexahedron (with 12 edges) is a cube where all the faces are squares An irregular hexahedron (with 12 edges) is a cuboid where two faces are equal squares and four are equal rectangles.
A solid is a 3-D object in which you can see all of the faces, edges, and vertices. A two dimensional figure is on paper and you cannot hold it in your hands.
Two.
A cone
an edge.
A cuboid.
A prism
They are the sets of points (or lines) where two faces meet.