A rollback does a couple of things: 1  Most importantly, a rollback reverts a question (or answer) back to a previous version in the edit history. The rollback action itself then appears as the most recent item in the edit history. 2  A rollback clears any offensive flags that have been set on a question.
In each of these whorls are one of four organs, including petals, sepals, stamens, and pistils. Petals and sepals do not play an active role in the reproductive process. Stamens and pistils, the flower's male and female reproductive organs, do aid in reproduction.
The four main parts of a flower are generally defined by their positions on the receptacle and not by their function. Many flowers lack some parts or parts may be modified into other functions and/or look like what is typically another part.