I've read/heard people saying "all of this" and "all of these" where this and these both refer to some plural entity. Are there any differences in using this and these in this way?
I'm guessing that the answer is that it doesn't matter, but wanted to make sure.
For example (taken from here)
Participants commonly report increased mental clarity, improved quality of sleep, higher energy levels, and better moods. You can achieve all of this WITHOUT ...
Shouldn't it be "You can achieve all of these"?