How to change size from specific geom in ggplot2?

Question

I have a ggplot containing 2 layers geom_point and geom_line as shown below.

gp <- ggplot(data = mtcars , aes(x = disp , y = hp)) +         


        

Answer 1

You can override specific properties of the plot keeping rest of them as it is

library(ggplot2)
gp + geom_point(size = 5)

Or with geom_line

gp + geom_line(size = 5, color = "red")