The temperate phage lambda can undergo two life cycles depending on the environmental cues. During which cycle does phage lambda form a prophage? Choose one: A. lysogeny B. burst cycle C. lytic cycle D. slow-release cycle

Explanation:

Lamda phase can undergo two types of life cycle i) lytic and ii)  lysogeny depemding on situation.

Lysogeny life cycle: In lysogeny life cycle, phase insert its DNA into the bacterial DNA , this inserted DNA is known as  prophage. This can be remains in the form of  prophage for a very long period, or in the stress conditions,  prophage can become virulent and removed himself from the bacterial DNA. After this, bacteria can undergo lytic cycle and produce many phase particles.

it is either c or d and i know for sure it is not a or b

substitution is the answer in this case