Rectangular prism
Rectangle
Yes
Yes
rectangle
That is a rectangular solid.
rectangle
a rectangular prism, a cuboid
A shoe box can be in the shape of a cuboid that has 6 faces, 12 edges and 8 vertices
A rectangle.
A rectangular cuboid
U don't know
It could be a rectangular cuboid prism
A cuboid prism
yes
Solid density is just that - the weight of a fixed volume of the solid material. But if the material is not solid, that is, if it is divided into particles or grains, or "chunks" or the like, then they will not "pack down" and be as dense as a solid volume of the material. Let's try an example. If we have a shoe box full of glass marbles, it will have a given weight. And, if we have the dimensions of the box, we can take the weight and the volume of the box and make a density calculation. But the box won't actually be "solid glass" as it would if we could ignore the "packing" of the spheres. The marbles end up leaving space between and around them when we put them in the box. They're round, and they can't take up all the space in the box. They simply can't. Because they can't take up all the volume in the box, it gives rise to what we call bulk density. If we take the the density of the glass from which the marbles are made, we could find the weight of a volume of that glass that was equal to the volume of the shoe box. The weight of the glass in a shoe box that is "solid glass" will be higher than that of the weight of the marbles in a full box. And that's because it is based on our filling the box with marbles and not being able to make the spaces between the marbles disappear. Got links if you want 'em.
A cube or cuboid have 6 flat surfaces and 8 vertices. (A cuboid means shaped like a cube - an example being a shoe box.)