I am studying about PCA and in which I have studied that using biplot function we can plot both vector and points same graph which help us analyzing the PCA but in biplot I have read about cex argument but I am not able to understand it what it does.

library(lattice)

my.wines <- read.csv(“http://steviep42.bitbucket.org/YOUTUBE.DIR/wines.csv”, header=TRUE)

pairs(my.wines[,-1])

my.prc <- prcomp(my.wines[,-1], center=TRUE, scale=TRUE)

biplot(my.prc, cex=c(1, 0.7))