"These" or "Those" in an essay?

Question

I'm confused with whether I should use "these" or "those" in the context of writing a paper or report in the specific example below. I don't know how I can do it differently:

1) To detect abnormal features in a patient's organs, a health provider can tap a patient's body parts to cause sound waves. _____(These/ Those) sound waves will be reflected by a patient's organs and heard by a health provider.

2) Unsuccessful interaction can lead to a patient's negative health outcomes. ______(This/ That) is because unsuccessful communication...

3) Herbs can be used to make medicine. Because of (this/that).......

4) Tapping is a good technique for abnormal findings. _____(This/That) technique can also be used to.....

Every time I'm in the situation above. I don't know what to do.

On one hand, I feel that "this" and "that" (or the pair "these" and "those") can be interchangeable in the case of writing a report or a paper as:

"This"/"These" can be used to refer to something mentioned in the previous sentence

"That"/"Those" can be used to refer to something that happens in real life or in the outside world.

On the other hand, I think there should be rules when this,that,these, and those are being used in an essay/ report/ paper.

Answer 1

In all the examples you give, use "this" or "these".

While you would be understood if you used "that", the thing you are referring to is your idea, and so it remains psychologically close to you.

So in the first example, you introduce the idea of "sound waves". It is not the physical location that matters, but the idea. In each case it is "these sound waves that I am talking about" or "This interaction that I say is unsuccessful"

You could use "that" or "those" when you introduce a comparison

... these sound waves can be heard by the health provider. This is different from an ultrasound system, as those sound waves are too high to be heard.