Grid line consistent with ticks on axis

Question

I am embarrassed to ask this simple question, but has been in kicking my mind for several days whenever I create a plot:

plot (x = 1:10, y = rnorm (10, 5, 2)         


        

Answer 1

From ?grid description of the nx and ny arguments:

When NULL, as per default, the grid aligns with the tick marks on the corresponding default axis (i.e., tickmarks as computed by axTicks)

plot (x = 1:10, y = rnorm (10, 5, 2)) 
grid (NULL,NULL, lty = 6, col = "cornsilk2")