Examples of aromatic compounds: benzene, toluene, xylene, anilin, etc.
The molecule you are referring to is cholesterol. It has a structure composed of four fused rings, three of which are six carbon rings and one is a five carbon ring.
Only some cyclic carbon atom rings can properly be called aliphatic: those without any carbon-carbon double bonds or aromatic ring bonds. For example, cyclohexane is aliphatic, but cycolohexene and benzene, which all contain rings of six carbon atoms, are not.
Yes. Carbon has many compounds and a number of allotropes where it forms rings.
The stress on the carbon=carbon bonds is minimal in a hexagonal carbon ring. Fewer carbons raises the stress and increases the likelihood of bonds breaking.
Most fuels combust into mainly water and carbon dioxide. Depending on the purity of the fuel you also get nitrogen compounds like NO, NO2 and sulphur componds like SO2
yes
Yes. Carbon has many compounds and a number of allotropes where it forms rings.
There are 27 carbon atoms in a molecule of cholesterol. 10 are not contained in the rings.
Yes. you can get at Kevlar tungsten wedding rings http://madtungsten.com/product-category/kevlar-carbon-fiber-rings/
Plastics are organic materials.
Four or more. The basic steroid "backbone" is a set of four fused ring systems, three of which have six carbon atoms and one of which has five carbon atoms.
Steroids