We learnt about the "central dogma" of molecular biology:

(a) Each of the three processes - replication, transcription and translation - involves a machinery with several entities participating. For each process, name the molecular machine that plays a critical and major role in that process, and state within one sentence the function of each of them.

(b) Errors made during DNA replication are far lesser compared to errors made during transcription. Why does it make sense that replication is more accurate than transcription?