1. An underdeveloped DNA molecule would result in mutations. On the genetic level, this could mean entire traits are deleted or that an early stop occurs in transcription, which could cut off parts of instructions.
2. Genetic code is the nucleotide sequence of a gene while the gene expression is how these sequences are used to make functioning amino acids and proteins to create DNA.
3. In each cell itself there are roughly 42 million proteins.
This kind of wave is called a longitudinal wave and an example of such a wave is a sound wave. The center of compression can be analogous to the top of a crest of a transverse wave while the center of the rarefaction would be analogous to the bottom of the trough of a transverse wave.