Final answer:
Cytosine methylation can be lost in cells due to passive demethylation during replication.
Step-by-step explanation:
True - Cytosine methylation can indeed be lost in cells simply due to passive demethylation during replication.
During DNA replication, the methylation marks on the cytosine bases can be enzymatically removed, resulting in the loss of cytosine methylation.
This process is known as passive demethylation.