What is the difference between the phrases "What is this"

What is the difference between the phrases “What is this” and “What is that”?
And what is the difference between “these” and “those”?

‘this’ - if something not far from you is (plural - these) - Russian -этот; German - dieser
‘that’ - if something further from you is (plural - those)- Russian - тот; German- jener
For example: this house - it’s here, not far; that house - it’s there, not close to you.

imagine picking up a piece of fruit that you’ve never seen before, picking it off the tree and holding it in your hand. You would say to your friend “What is this?”. If that same fruit is high up in a tree and you are pointing to it, you’d say “What is that?”