This resembles closely the composition of the jovian planets. Strictly speaking, the composition detected is only for the photosphere and chromosphere, but it is most likely similar throughout with the exception of the core whose composition is constantly changing. The photosphere is too bright to be able to see the cooler chromosphere directly above. Also, since the density of the chromosphere is low, there are fewer atoms to emit photons. The chromosphere can be seen during an eclipse around the outer edge of the moon or through an H-alpha filter.
Spicules are the result of small storms in the chromosphere.
They are small ejections of hot gas and tend to congregate around the edges of supergranules. The Transition Zone os the part of the solar atmosphere separating the chromospere and corona. It is the region in which the temperature rises drastically on the way to the corona. In this region, the spectral lines take on a different appearance due to the increased temperature. This higher temperature ionizes the atoms there.