Exercise 35B: PCA plot for RNASeq data

What is the name of the function that calculates the principal components? Answer should be one word.

What is the input for the prcomp function? 

I want to scale the genes. Which argument(s) of prcomp() do I need to set for this?

Which function from the ggfortify package will create the PCA plot? Answer should be one word.

Do you want to see the code for making the PCA plot?