A temperate phage is one that a. is restricted to infecting a single species. b. is incapable of lysing the host cell. c. grows best at moderate temperatures. d. can undergo lysogeny.

d. can undergo lysogeny.

Explanation:

Virus can use two reproduction cycle that is a lytic and lysogenic cycle. In the lytic cycle viral genome in the host cell produce new capsid protein by using host molecular machinery which results in making several new phase particles that lyse the host cell and come out.

In the lysogenic cycle, the virus does not lyse the cell but it goes into the latent phase by incorporating its genome into the host genome. The virus genome replicates with the host genome lysogenic cycle. So the phage which undergo lysogeny is called temperate phage. So the correct answer is d.