I think the answer is NUCLEUS.
Hope it helps!
Answer:
B
Explanation:
Commensalism is a type of symbiotic relationship in which one species benefits, while the other species is neither harmed nor helped.
Answer:
A retrovirus is an RNA virus that is duplicated in a host cell using the reverse transcriptase enzyme to produce DNA from its RNA genome. The DNA is then incorporated into the host's genome by an integrase enzyme. The virus thereafter replicates as part of the host cell's DNA.