A lysogenic bacterium?

A lysogenic bacterium is characterized by the presence of a prophage, which is a viral genome integrated into the bacterial chromosome. This integration allows the bacterium to replicate normally while carrying the viral DNA, which can later be induced to enter the lytic cycle, leading to the production of new virions. During the lysogenic phase, the prophage may also confer new properties or enhance the survivability of the bacterium, such as resistance to certain environmental stresses or the ability to produce toxins, which can be beneficial for both the bacterium and the viral genome.

The other options do not accurately describe the nature of a lysogenic bacterium. For example, while some bacteria can cause lysis of others, that behavior is not a defining characteristic of lysogenic bacteria. On the other hand, it is incorrect to state that lysogenic bacteria cannot support the replication of a virulent phage, as lysogenic bacteria can indeed support phage replication under the right conditions once the prophage is induced to enter the lytic cycle. Lastly, while some lysogenic bacteria can be human pathogens, it is not a definitive trait of all lysogenic bacteria, making this option less applicable. The defining feature remains the presence of the prophage, making it