Answer:
I wasn't quite sure what virus you were referring to in your question, but here's a general answer: Viruses use their host cells' machinery to replicate themselves.
If they are a specific type of virus known as a retrovirus, they have the ability to use the host cells' enzymes to change the RNA contained within the virus into DNA (via some type of replication I suppose).
In other cases, if they contain DNA instead of RNA (that is, the virus), they can use the host cell's machinery to create RNA via enzymes involved in transcription and/or they can incorporate that DNA into the host cell's DNA. This is part of a type of viral replication cycle known as the lysogenic cycle.
In another type of viral replication cycle known as the lytic cycle, the virus simply has itself and its genome duplicated until the host cell bursts, releasing the viral material. Here, again, the virus uses the host cell's machinery to replicate itself.
Answer:
I think true statement is A.
The correct answer is stabilizing selection.
Stabilizing selection is a kind of natural selection in which the mean of the population steadies on a specific non-extreme trait value. This is considered to be the most general process of action for natural selection as the majority of the traits do not seem to vary radically with time.
Stabilizing selection is the reverse of disruptive selection. In spite of preferring individuals with extreme phenotypes, it favors the transitional variants. Stabilizing selection seems to eradicate the more extreme phenotypes, resulting in the reproductive success of the average or norm phenotypes.
This signifies that the most general phenotype in the population is chosen and continues to govern in the coming generations. As the majority of the traits vary slightly with time, stabilizing selection is considered to be the most usual kind of selection in the majority of the populations.
I believe the answer is that the CFCs cause low ozone concentrations in the atmosphere.
Sorry if I'm wrong, hope this helps.
