title: How to get only certain plots when plot() returns multiple plots
body: <p>When I use plot() with a linear model, I get 4 plots, A normal QQ plot, residuals vs fitted, etc.</p>
  
  <p>How do I get it so I only get the normal QQ plot, or only residual plot. I did it before, I think there is an argument like number= n or something. I need to know so I can save images for all the plots.</p>