Because it has equilateral triangles.
Statistically speaking, the mean is the most stable from sample to sample. Whereas, the mode is the least stable statistically speaking from sample to sample.
The question is not clear. Hardest, as in the most rigid, is a triangular prism (or tetrahedron). Hardest, to work the geometry of, is probably an irregular blob.
The most simple pyramid is a tetrahedron. This pyramid has four faces, all triangles. If the pyramid was a cone then it could have two faces.
Possibly, the most common and stable isotope of Nitrogen.
a pyramid, in the sense that most people think of has a square base, with 4 triangle 'sides', which would be 5 faces. A regular tetrahedron has 4 equilateral triangles as faces.
A Tetrahedron. The most common form of a tetrahedron is called a regular tetrahedron, or a pyramid
It is not most stable
The one he is most famous for is dynamite, and others involve similar processes of securing nitroglycerine into inert structures to make it stable.
There are 25 natures available, most raising one stat by 10% and decreasing another by 10%. However, there are five natures that are neutral, and don't improve or hinder any stats. Psypokes.com has a good table displaying all natures, their effects, and likes/dislikes. It can be found here: http://www.psypokes.com/lab/natures.php
Tritium is not the most stable isotope known.
neon is most stable
http://myamazingfact.blogspot.com/2009/02/18-of-natures-most-powerful-medicinal.html
Intermediate filaments are the most stable.
A shape formed by four triangles would have to be a tetrahedron. But I believe that a tetrahedron can have at most three right angled triangles. One with four of them is, I think, impossible.
My money is on the tetrahedron, triangles tend to be very sturdy.
as stable as most
The atomic mass of the most stable isotope of Roentgenium is 281. This most stable isotope decays in around 36seconds. Oddly, it's most stable isotope has the same atomic mass as the most stable isotope of the element before: Darmstadtium.