Science based EPQ source evaluation

Hi,
I'm currently doing a very scientific based EPQ on optic nerve regeneration.

I think i'm almost done but ive been told i need to add some "source evaluation". Where and how do i do this ?

Should i add a section/paragraph to the end of my EPQ called "source evaluation" and then chose 2-3 sources to analyse? Ive heard some people did an actual table at the end of their dissertation ?

Or should i leave that to talk about in my presentation ?

And finally, what sort of things do i talk about for the sources as most of my sources are from medical research journals online ???

Thanks