Exercise

1. Use the ggtitle layer to add the plot title.

  ggtitle('Radial Glia')

2. Increase the size of the plot title to be 1.5 times the default value.

  theme(plot.title = element_text(size = rel(1.5))) 
  

3.Remove the legend by adding a theme() layer with the argument legend.position.

theme(legend.position = "none") 

4. Remove the gridlines by adding another theme() layer with the argument panel.grid.

theme(panel.grid = element_blank()) 

5. Add the following new layer to the code chunk theme(plot.title=element_text(hjust=0.5)). What does it change?

It centers the plot title.

theme(plot.title=element_text(hjust=0.5)) 

6. How many theme() layers can be added to a ggplot code chunk, in your estimation?

There is no upper limit.