245 reported on the synthesis of linear but alsobranched polymers prepared by di-, tri-, and tetra-alkyne andazide monomers like the combination of tripropargylamine(B 3)and(dihydroxymethyl)(diazidomethyl)amine(A 2)(com-pare the general outline in Scheme 17).
When discussing mineral formations in caves, we often talk about stalactites and stalagmites. A stalactite is an icicle-shaped formation that hangs from the ceiling of a cave, and is produced by precipitation of minerals from water dripping through the cave ceiling. Most stalactites have pointed tips.
A meteorite is a meteoroid that reaches the surface of the Earth without being completely vaporized. Meteor's come in a range of sizes, from dust-sized which we see as reflected sunlight in the orbital plane of the Solar System (called zodiacal light) to house-sized. When a meteor enters the atmosphere friction causes ablation of its surface (i.e. it burns up).