Building an image

I am new in building images in docker. I would like to ask the following:
1- What is the difference between image rocker/r-base and image rocker/r-ver? because I don’t know when I should use them, or should I use both?

2- When I use rocker/rbase:4.3.2 and want to run Rscript, I got always:
“Rscript not found” like the following:
Step 14/14 : RUN Rscript /install_packages_allprojects1.R
—> Running in d0ba0f9029cc
/bin/sh: 1: Rscript: not found

But it solved when I add:
RUN apt-get update -qq && apt-get -y --no-install-recommends install r-base

So what the difference between this line and importing the image of rocker/r-base itself using FROM rocker/rbase:4.3.2

3- Despite using rbase:4.3.2, I got this error while install package actuar:
ERROR: this R is version 3.6.3, package ‘actuar’ requires R >= 4.1.0

Thanks in advance

This is not a docker related question, but more a “rocker” one.
But, a quick googlin’ got me: Rocker Project - r-ver

3 problem you are facing indicates the actuar indicate that it is need of R version 4.1.0, and your current R version is 3.6.3. For this you have to use image which has higher R version 4.1.0 or higher.