DNA replication involves many different steps. By number, arrange the following four steps in order from start to finish: 1) DNA polymerase [POL-uh-muh-rays] synthesizes a new DNA strand, 2) DNA ligase [LY-gays] repairs nicks in the phosphodiester [fos-foh-dy-ES-tuhr] backbone, 3) replication bubble opens at origin, 4) primase builds the primer.