Cell division by meiosis forms gametes. Three steps of this process involve DNA replication, a first cellular division, and a second cellular division. The graph below shows the mean mass of DNA per cell before, during, and after meiosis for a particular animal species.
Use the graph to answer the following questions:
a.[1]
During which time interval is the DNA in the chromosomes being copied?
b.[1]
At which two times does a cell division event occur?
c.[1]
What is the mean mass of DNA (in pg\text{pg}pg) in a completed gamete?
d.[1]
What is the expected mean mass of DNA (in pg\text{pg}pg) in a zygote formed by the fusion of two of these gametes?