A tetrahedron is triangular based pyramid that can be spread out into 4 nets
There are 8 possible nets
If you take a look at this graphic on wikipedia http://en.wikipedia.org/wiki/File:The_11_cubic_nets.svg It will show all 11 nets of the cube.
There are many different nets for a cuboid, a very simple one is in the shape of a T with three units across and three units down.
There is only one net to a triangular pyramid.
A tetrahedron is triangular based pyramid that can be spread out into 4 nets
A tetrahedron has two nets, corresponding to "upwards" and "downwards" folds; i.e. you can fold a piece of paper into a polyhedron by bending all the edges in two different directions.
11 nets
There are only 11 different types of cube nets if you use six squares.
a rectangular prism has 12 different nets
there are 11 nets that make a cube
6
11
18
it has 0 nets because it is impossible to make a perfect ball /circular globe out of a flat piece of paper
Three if mirror images are considered different and two otherwise.
There are approx 6.4 million topologically different convex dodecahedron, plus concave one. Each one of these will have several nets.