Which life process is necessary for the survival of a species but not necessary

Reproduction because the life process necessary for the survival of a species but not for the survival of an individual organism.

Bacteriophages like other viruses, consist primarily of a protein coat and ackaged DNA. Description on the function of critical enzyme; DNA helicase unwinds its two strands and makes a replication fork. The enzyme primase puts down a short RNA strand complementary to a short sequence of DNA being replicated to initiate a new strand of DNA. DNA polymerase elongates the new strand of DNA, building a new anti-parallel strand.