1. sewage system - facility consisting of a system of sewers for carrying off liquid and solid sewage. sewage works, sewer system. facility, installation - a building or place that provides a particular service or is used for a particular industry; "the assembly plant is an enormous facility"
Replication is the process where DNA molecules copies itself to form another DNA molecule during cell division. it involves several enzymes which includes DNA helicase, the enzyme that unwounds the DNA double helix. RNA primase, it is an enzyme that creates an RNA primer. DNA polymerase, it is the enzyme that matches and lays down nucleotides to form the new DNA daughter. DNA ligase joins the Okazaki fragments by catalysing the formation of phosphodiester bond.