Stuttering is a speech disorder characterized by repetition of sounds, syllables, or words; prolongation of sounds; and interruptions in speech known as blocks. An individual who stutters exactly knows what he or she would like to say but has trouble producing a normal flow of speech.
The 3 types of RNA are mRNA is a long strand, the tRNA is shaped  like a clover leaf pattern. The third shape is Ribosomal RNA, it  is a very complex shape.
There is one single type of DNA while there are many types of RNA that have different functions such as mRNA (carries DNA message to cytoplasm), tRNA (carries amino acids to mRNA and Ribosomes), rRNA (Ribosomal RNA, workbench for protein synthesis). DNA cannot catalyze its own synthesis while RNA can.