Final answer:
Phages can replicate in harmony with their host cell through lysogeny, where the phage's DNA is incorporated into the host's genome, and through transduction, which involves the transfer of DNA between bacteria.
Step-by-step explanation:
Two ways that phage can replicate in harmony with their host cell without directly lysing it are lysogeny and transduction. In lysogeny, a bacteriophage's DNA is incorporated into the host's genome as a prophage, where it can be replicated along with the host's DNA and passed on to subsequent generations without causing immediate harm to the host. This process can lead to lysogenic conversion, altering the host's phenotype. Transduction is another non-lytic mechanism where a bacteriophage can transfer DNA from one bacterium to another, potentially conferring new traits such as antibiotic resistance or metabolic capabilities without destroying the host cell.