이것은 ~입니다.

Yes, you can use '이것' for animals, but many pet owners prefer '이 아이' (this child) or '우리 강아지' (our puppy) to show affection.

'이건' is just the shortened version of '이것은'. They mean the exact same thing, but '이건' is more common in speech.

Yes, '입니다' is the formal version of 'to be' and must follow a noun. You cannot use it directly after an adjective or verb.

You use '이것은 ~이/가 아닙니다'. For example: '이것은 사과가 아닙니다' (This is not an apple).

'이게' is the contraction of '이것이' (subject marker). It's used when you want to focus on the object itself rather than the topic.

Yes, but only if you are texting someone you need to be formal with, like a professor or a client. With friends, use '이야'.

In Korea, pointing with one finger can be seen as aggressive. It is better to gesture with an open palm toward the object.

You can ask '이것은 무엇입니까?' (What is this?) or '이게 뭐예요?' (What is this? - polite).

No! Korean verbs don't change for singular or plural. '이것은 책입니다' can mean 'This is a book' or 'These are books'.

Use '저것' (jeogeot) when the object is far away from both you and the person you are talking to.

Yes, the basic structure is the same, though the intonation and some vocabulary might differ.

Yes, when showing a photo on your phone, you can say '이것은 제 고향입니다' (This is my hometown).